Margins Study Assistant

Chapter 1

Essential Ideas

Summary

The basic building block of matter is the atom, the smallest unit of an element that can enter into combinations with atoms of the same or other elements. Chemists use the scientific method to perform experiments, pose hypotheses, and formulate laws and develop theories, so that they can better understand the behavior of the natural world. In many substances, atoms are combined into molecules. Chemistry deals with the composition, structure, and properties of matter, and the ways by which various forms of matter may be interconverted.

Key terms

element: substance that is composed of a single type of atom; a substance that cannot be decomposed by a chemical change
law: statement that summarizes a vast number of experimental observations, and describes or predicts some aspect of the natural world
scientific method: path of discovery that leads from question and observation to law or hypothesis to theory, combined with experimental verification of the hypothesis and any necessary…
symbolic domain: specialized language used to represent components of the macroscopic and microscopic domains, such as chemical symbols, chemical formulas, chemical equations, graphs, drawings…
basic building block of matter: the atom, the smallest unit of an element that can enter into combinations with atoms of the same or other elements
atom: smallest particle of an element that can enter into a chemical combination
molecule: bonded collection of two or more atoms of the same or different elements
chemistry: study of the composition, properties, and interactions of matter

Chapter 2

Atoms, Molecules, and Ions

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Summary

Samples of a particular compound all have the same elemental proportions by mass. Thomson’s cathode ray tube showed that atoms contain small, negatively charged particles called electrons. Millikan discovered that there is a fundamental electric charge—the charge of an electron. The ancient Greeks proposed that matter consists of extremely small particles called atoms.

Key terms

ion: electrically charged atom or molecule (contains unequal numbers of protons and electrons)
electron: negatively charged, subatomic particle of relatively low mass located outside the nucleus
structural isomer: one of two substances that have the same molecular formula but different physical and chemical properties because their atoms are bonded differently
metal: element that is shiny, malleable, good conductor of heat and electricity
periodic law: properties of the elements are periodic function of their atomic numbers
structural formula: shows the atoms in a molecule and how they are connected
binary acid: compound that contains hydrogen and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H + ions when dissolved in water)
inner transition metal: (also, lanthanide or actinide) element in the bottom two rows; if in the first row, also called lanthanide, or if in the second row, also called actinide

Chapter 3

Composition of Substances and Solutions

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Summary

Due to the use of the same reference substance in defining the atomic mass unit and the mole, the formula mass (amu) and molar mass (g/mol) for any substance are numerically equivalent (for example, one H 2 O molecule… The formula mass of a substance is the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units. The formula mass of a covalent compound is also called the molecular mass. The mass in grams of 1 mole of substance is its molar mass.

Key terms

formula mass: sum of the average masses for all atoms represented in a chemical formula; for covalent compounds, this is also the molecular mass
formula mass of a substance: the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units
mole: amount of substance containing the same number of atoms, molecules, ions, or other entities as the number of atoms in exactly 12 grams of 12 C
chemical identity of a substance: defined by the types and relative numbers of atoms composing its fundamental entities (molecules in the case of covalent compounds, ions in the case of ionic compounds)
mass percentage: ratio of solute-to-solution mass expressed as a percentage
percent composition: percentage by mass of the various elements in a compound
molar mass: mass in grams of 1 mole of a substance
solvent: solution component present in a concentration that is higher relative to other components

Chapter 4

Stoichiometry of Chemical Reactions

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Summary

Chemical reactions in aqueous solution that involve ionic reactants or products may be represented more realistically by complete ionic equations and, more succinctly, by net ionic equations Formulas for the substances undergoing the change (reactants) and substances generated by the change (products) are separated by an arrow and preceded by integer coefficients indicating their relative numbers. Balanced equations are those whose coefficients result in equal numbers of atoms for each element in the reactants and products. A large number of important reactions are included in three categories: precipitation, acid-base, and oxidation-reduction (redox).

Key terms

stoichiometry: relationships between the amounts of reactants and products of a chemical reaction
complete ionic equation: chemical equation in which all dissolved ionic reactants and products, including spectator ions, are explicitly represented by formulas for their dissociated ions
net ionic equation: chemical equation in which only those dissolved ionic reactants and products that undergo a chemical or physical change are represented (excludes spectator ions)
precipitation reaction: reaction that produces one or more insoluble products; when reactants are ionic compounds, sometimes called double-displacement or metathesis
oxidation: process in which an element’s oxidation number is increased by loss of electrons
reduction: process in which an element’s oxidation number is decreased by gain of electrons
product: substance formed by a chemical or physical change; shown on the right side of the arrow in a chemical equation
reactant: substance undergoing a chemical or physical change; shown on the left side of the arrow in a chemical equation

Chapter 5

Thermochemistry

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Summary

Kinetic energy (KE) is the energy of motion; potential energy is energy due to relative position, composition, or condition. The thermal energy of matter is due to the kinetic energies of its constituent atoms or molecules. Temperature is an intensive property of matter reflecting hotness or coldness that increases as the average kinetic energy increases. Heat is the transfer of thermal energy between objects at different temperatures.

Key terms

thermochemistry: study of measuring the amount of heat absorbed or released during a chemical reaction or a physical change
temperature: intensive property of matter that is a quantitative measure of “hotness” and “coldness”
joule (J): SI unit of energy; amount of energy used when a force of 1 newton moves an object 1 meter, 1 J = 1 kg m 2 /s 2 and 4.184 J = 1 cal
kinetic energy: energy associated with an object's motion, equal to one-half the product of the object's mass and the square of its velocity, 1 2 m v 2 (where m = mass and v = velocity)
first law of thermodynamics: internal energy of a system changes due to heat flow in or out of the system or work done on or by the system
potential energy: energy of a particle or system of particles derived from relative position, composition, or condition
thermal energy: kinetic energy associated with the random motion of atoms and molecules
thermal energy of matter: due to the kinetic energies of its constituent atoms or molecules

Chapter 6

Electronic Structure and Periodic Properties of Elements

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Summary

Electromagnetic radiation that passes through two closely spaced narrow slits having dimensions roughly similar to the wavelength will show an interference pattern that is a result of constructive and destructive… Standing waves exhibit quantization, since their wavelengths are limited to discrete integer multiples of some characteristic lengths. The energy of a photon is related to the frequency (or alternatively, the wavelength) of the radiation as E = hν (or E = h c λ ), where h is Planck's constant. Other important wave phenomena include standing waves, periodic oscillations, and vibrations.

Key terms

standing wave: (also, stationary wave) localized wave phenomenon characterized by discrete wavelengths determined by the boundary conditions used to generate the waves; standing waves are…
energy of a photon: related to the frequency (or alternatively, the wavelength) of the radiation as E = hν (or E = h c λ ), where h is Planck's constant
interference pattern: pattern typically consisting of alternating bright and dark fringes; it results from constructive and destructive interference of waves
electromagnetic radiation: energy transmitted by waves that have an electric-field component and a magnetic-field component
wave: oscillation of a property over time or space; can transport energy from one point to another
photon: smallest possible packet of electromagnetic radiation, a particle of light
quantization: limitation of some property to specific discrete values, not continuous

Chapter 7

Chemical Bonding and Molecular Geometry

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Summary

In pure covalent bonds, the electrons are shared equally. In polar covalent bonds, the electrons are shared unequally, as one atom exerts a stronger force of attraction on the electrons than the other. Covalent bonds form when electrons are shared between atoms and are attracted by the nuclei of both atoms. The ability of an atom to attract a pair of electrons in a chemical bond is called its electronegativity.

Key terms

covalent bond: bond formed when electrons are shared between atoms
polar covalent bond: covalent bond between atoms of different electronegativities; a covalent bond with a positive end and a negative end
pure covalent bond: (also, nonpolar covalent bond) covalent bond between atoms of identical electronegativities
electronegativity: tendency of an atom to attract electrons in a bond to itself
axial position: location in a trigonal bipyramidal geometry in which there is another atom at a 180° angle and the equatorial positions are at a 90° angle
equatorial position: one of the three positions in a trigonal bipyramidal geometry with 120° angles between them; the axial positions are located at a 90° angle
octahedral: shape in which six outside groups are placed around a central atom such that a three-dimensional shape is generated with four groups forming a square and the other two forming…

Chapter 8

Advanced Theories of Covalent Bonding

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Summary

Valence bond theory describes bonding as a consequence of the overlap of two separate atomic orbitals on different atoms that creates a region with one pair of electrons shared between the two atoms. When they overlap in a fashion that creates a node along this axis, they form a π bond When the orbitals overlap along an axis containing the nuclei, they form a σ bond. We can use hybrid orbitals, which are mathematical combinations of some or all of the valence atomic orbitals, to describe the electron density around covalently bonded atoms.

Key terms

valence bond theory: description of bonding that involves atomic orbitals overlapping to form σ or π bonds, within which pairs of electrons are shared
node: plane separating different lobes of orbitals, where the probability of finding an electron is zero
overlap: coexistence of orbitals from two different atoms sharing the same region of space, leading to the formation of a covalent bond
hybridization: model that describes the changes in the atomic orbitals of an atom when it forms a covalent compound
hybrid orbital: orbital created by combining atomic orbitals on a central atom
diamagnetism: phenomenon in which a material is not magnetic itself but is repelled by a magnetic field; it occurs when there are only paired electrons present
paramagnetism: phenomenon in which a material is not magnetic itself but is attracted to a magnetic field; it occurs when there are unpaired electrons present
pi bond (π bond): covalent bond formed by side-by-side overlap of atomic orbitals; the electron density is found on opposite sides of the internuclear axis

Chapter 9

Gases

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Summary

Atmospheric pressure is measured using a barometer; other gas pressures can be measured using one of several types of manometers The pressure of a gas may be expressed in the SI unit of pascal or kilopascal, as well as in many other units including torr, atmosphere, and bar. The pressure of a given amount of gas is directly proportional to its absolute temperature, provided that the volume does not change (Amontons’s law). The volume of a given gas sample is directly proportional to its absolute temperature at constant pressure (Charles’s law).

Key terms

Amontons’s law: (also, Gay-Lussac’s law) pressure of a given number of moles of gas is directly proportional to its kelvin temperature when the volume is held constant
Boyle’s law: volume of a given number of moles of gas held at constant temperature is inversely proportional to the pressure under which it is measured
Charles’s law: volume of a given number of moles of gas is directly proportional to its kelvin temperature when the pressure is held constant
Avogadro’s law: volume of a gas at constant temperature and pressure is proportional to the number of gas molecules
manometer: device used to measure the pressure of a gas trapped in a container
bar: (bar or b) unit of pressure; 1 bar = 100,000 Pa
barometer: device used to measure atmospheric pressure
torr: unit of pressure; 1 torr = 1 760 atm

Chapter 10

Liquids and Solids

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Summary

Intermolecular attractive forces, collectively referred to as van der Waals forces, are responsible for the behavior of liquids and solids and are electrostatic in nature. Dipole-dipole attractions result from the electrostatic attraction of the partial negative end of one polar molecule for the partial positive end of another. The temporary dipole that results from the motion of the electrons in an atom can induce a dipole in an adjacent atom and give rise to the London dispersion force. Hydrogen bonds are a special type of dipole-dipole attraction that results when hydrogen is bonded to one of the three most electronegative elements: F, O, or N

Key terms

dispersion force: (also, London dispersion force) attraction between two rapidly fluctuating, temporary dipoles; significant only when particles are very close together
van der Waals force: attractive or repulsive force between molecules, including dipole-dipole, dipole-induced dipole, and London dispersion forces; does not include forces due to covalent or ionic…
intermolecular force: noncovalent attractive force between atoms, molecules, and/or ions
dipole-dipole attraction: intermolecular attraction between two permanent dipoles
body-centered cubic unit cell: simplest repeating unit of a body-centered cubic crystal; it is a cube containing lattice points at each corner and in the center of the cube
cubic closest packing (CCP): crystalline structure in which planes of closely packed atoms or ions are stacked as a series of three alternating layers of different relative orientations (ABC)
face-centered cubic unit cell: simplest repeating unit of a face-centered cubic crystal; it is a cube containing lattice points at each corner and in the center of each face
hexagonal closest packing (HCP): crystalline structure in which close packed layers of atoms or ions are stacked as a series of two alternating layers of different relative orientations (AB)

Chapter 11

Solutions and Colloids

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Summary

The solutes are the other components typically present at concentrations less than that of the solvent. Electrolytes may be covalent compounds that chemically react with water to produce ions (for example, acids and bases), or they may be ionic compounds that dissociate to yield their constituent cations and anions, when… Dissolution of an ionic compound is facilitated by ion-dipole attractions between the ions of the compound and the polar water molecules. A solution forms when two or more substances combine physically to yield a mixture that is homogeneous at the molecular level.

Key terms

colloid: (also, colloidal dispersion) mixture in which relatively large solid or liquid particles are dispersed uniformly throughout a gas, liquid, or solid
ionic compound: facilitated by ion-dipole attractions between the ions of the compound and the polar water molecules
solutes: the other components typically present at concentrations less than that of the solvent
solvent: the most concentrated component and determines the physical state of the solution
ion-dipole attraction: electrostatic attraction between an ion and a polar molecule
ideal solution: solution that forms with no accompanying energy change
electrolyte: substance that produces ions when dissolved in water

Chapter 12

Kinetics

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Summary

Relations between different rate expressions for a given reaction are derived directly from the stoichiometric coefficients of the equation representing the reaction Rate laws ( differential rate laws ) provide a mathematical description of how changes in the concentration of a substance affect the rate of a chemical reaction. The rate of a chemical reaction is affected by several parameters. If temperature or reactant concentration is increased, the rate of a given reaction generally increases as well.

Key terms

rate expression: mathematical representation defining reaction rate as change in amount, concentration, or pressure of reactant or product species per unit time
rate law: (also, rate equation) (also, differential rate laws) mathematical equation showing the dependence of reaction rate on the rate constant and the concentration of one or more…
given reaction: derived directly from the stoichiometric coefficients of the equation representing the reaction
catalyst: substance that increases the rate of a reaction without itself being consumed by the reaction
rate of a chemical reaction: affected by several parameters
average rate: rate of a chemical reaction computed as the ratio of a measured change in amount or concentration of substance to the time interval over which the change occurred
frequency factor ( A ): proportionality constant in the Arrhenius equation, related to the relative number of collisions having an orientation capable of leading to product formation
instantaneous rate: rate of a chemical reaction at any instant in time, determined by the slope of the line tangential to a graph of concentration as a function of time

Chapter 13

Fundamental Equilibrium Concepts

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Summary

The system’s response to these disturbances is described by Le Châtelier’s principle: An equilibrium system subjected to a disturbance will shift in a way that counters the disturbance and re-establishes equilibrium. A reversible reaction is at equilibrium when the forward and reverse processes occur at equal rates. For a reaction at equilibrium, the composition is constant, and Q is called the equilibrium constant, K A homogeneous equilibrium is an equilibrium in which all components are in the same phase.

Key terms

equilibrium: state of a reversible reaction in which the forward and reverse processes occur at equal rates
homogeneous equilibrium: an equilibrium in which all components are in the same phase
heterogeneous equilibrium: an equilibrium in which components are in two or more phases
composition: constant, and Q is called the equilibrium constant, K
system’s response to these disturbances: described by Le Châtelier’s principle: An equilibrium system subjected to a disturbance will shift in a way that counters the disturbance and re-establishes equilibrium
Le Châtelier’s principle: an equilibrium subjected to stress will shift in a way to counter the stress and re-establish equilibrium
reversible reaction: chemical reaction that can proceed in both the forward and reverse directions under given conditions
equilibrium constant ( K ): value of the reaction quotient for a system at equilibrium; may be expressed using concentrations ( K c ) or partial pressures ( K p )

Chapter 14

Acid-Base Equilibria

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Summary

The species formed when a Brønsted-Lowry base gains a proton is the conjugate acid of the base. The compound that accepts the proton is called a Brønsted-Lowry base. Thus, an acid-base reaction occurs when a proton is transferred from an acid to a base, with formation of the conjugate base of the reactant acid and formation of the conjugate acid of the reactant base. Amphiprotic species can act as both proton donors and proton acceptors.

Key terms

autoionization: reaction between identical species yielding ionic products; for water, this reaction involves transfer of protons to yield hydronium and hydroxide ions
amphiprotic: species that may either donate or accept a proton in a Brønsted-Lowry acid-base reaction
pH: logarithmic measure of the concentration of hydronium ions in a solution
conjugate base: substance formed when an acid loses a proton
conjugate acid: substance formed when a base gains a proton
Brønsted-Lowry base gains a proton: the conjugate acid of the base

Chapter 15

Equilibria of Other Reaction Classes

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Summary

Complex ions are examples of Lewis acid-base adducts and comprise central metal atoms or ions acting as Lewis acids bonded to molecules or ions called ligands that act as Lewis bases. A Lewis acid is a species that can accept an electron pair, whereas a Lewis base has an electron pair available for donation to a Lewis acid. The equilibrium constant for an equilibrium involving the precipitation or dissolution of a slightly soluble ionic solid is called the solubility product, K sp , of the solid. For a heterogeneous equilibrium involving the slightly soluble solid M p X q and its ions M m+ and X n-

Key terms

complex ion: ion consisting of a central atom surrounding molecules or ions called ligands via coordinate covalent bonds
ligand: molecule or ion acting as a Lewis base in complex ion formation; bonds to the central atom of the complex
Lewis acid-base adduct: compound or ion that contains a coordinate covalent bond between a Lewis acid and a Lewis base
Lewis acid: any species that can accept a pair of electrons and form a coordinate covalent bond
Lewis base: any species that can donate a pair of electrons and form a coordinate covalent bond
slightly soluble ionic solid: called the solubility product, K sp , of the solid
common ion effect: effect on equilibrium when a substance with an ion in common with the dissolved species is added to the solution; causes a decrease in the solubility of an ionic species, or a…
selective precipitation: process in which ions are separated using differences in their solubility with a given precipitating reagent

Chapter 16

Thermodynamics

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Summary

Entropy ( S ) is a state function that can be related to the number of microstates for a system (the number of ways the system can be arranged) and to the ratio of reversible heat to kelvin temperature. A spontaneous process occurs without the need for a continual input of energy from some external source, while a nonspontaneous process requires such. Systems undergoing a spontaneous process may or may not experience a gain or loss of energy, but they will experience a change in the way matter and/or energy is distributed within the system It may be interpreted as a measure of the dispersal or distribution of matter and/or energy in a system, and it is often described as representing the “disorder” of the system

Key terms

entropy ( S ): state function that is a measure of the matter and/or energy dispersal within a system, determined by the number of system microstates; often described as a measure of the…
microstate: possible configuration or arrangement of matter and energy within a system
nonspontaneous process: process that requires continual input of energy from an external source
system: heated and when solutions form
standard entropy ( S °): entropy for one mole of a substance at 1 bar pressure; tabulated values are usually determined at 298.15 K
third law of thermodynamics: entropy of a perfect crystal at absolute zero (0 K) is zero
reversible process: process that takes place so slowly as to be capable of reversing direction in response to an infinitesimally small change in conditions; hypothetical construct that can only be…

Chapter 17

Electrochemistry

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Summary

Electrons are transferred from the reductant (in the anode half-cell) to the oxidant (in the cathode half-cell) through an external circuit, and inert solution phase ions are transferred between half-cells, through a… The half-reaction method is a systematic approach to balancing such equations that involves separate treatment of the oxidation and reduction half-reactions In electrochemistry, the potentials of cells and half-cells are thermodynamic quantities that reflect the driving force or the spontaneity of their redox processes. Redox reactions are defined by changes in reactant oxidation numbers, and those most relevant to electrochemistry involve actual transfer of electrons.

Key terms

half-reaction method: a systematic approach to balancing such equations that involves separate treatment of the oxidation and reduction half-reactions
potentials of cells and half-cells: thermodynamic quantities that reflect the driving force or the spontaneity of their redox processes
anode: electrode in an electrochemical cell at which oxidation occurs
cathode: electrode in an electrochemical cell at which reduction occurs
electrolytic cell: electrochemical cell in which an external source of electrical power is used to drive an otherwise nonspontaneous process
inert electrode: electrode that conducts electrons to and from the reactants in a half-cell but that is not itself oxidized or reduced
active electrode: electrode that participates as a reactant or product in the oxidation-reduction reaction of an electrochemical cell; the mass of an active electrode changes during the…

Chapter 18

Representative Metals, Metalloids, and Nonmetals

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Summary

These elements are representative metals, metalloids, and nonmetals. The outermost electrons of the alkaline earth metals (group 2) are more difficult to remove than the outer electron of the alkali metals, leading to the group 2 metals being less reactive than those in group 1. This section focuses on the periodicity of the representative elements. These are the elements where the electrons are entering the s and p orbitals.

Key terms

metalloid: element that has properties that are between those of metals and nonmetals; these elements are typically semiconductors
representative metal: metal among the representative elements
alkaline earth metal: any of the metals (beryllium, magnesium, calcium, strontium, barium, and radium) occupying group 2 of the periodic table; they are reactive, divalent metals that form basic oxides
alkali metals (group 1): very reactive, readily form ions with a charge of 1+ to form ionic compounds that are usually soluble in water, and react vigorously with water to form hydrogen gas and a
representative element: element where the s and p orbitals are filling
alkaline earth metals (group 2): more difficult to remove than the outer electron of the alkali metals, leading to the group 2 metals being less reactive than those in group 1
elements where the electrons: entering the s and p orbitals
disproportionation reaction: chemical reaction where a single reactant is simultaneously reduced and oxidized; it is both the reducing agent and the oxidizing agent

Chapter 19

Transition Metals and Coordination Chemistry

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Summary

The transition metals are elements with partially filled d orbitals, located in the d -block of the periodic table. The reactivity of the transition elements varies widely from very active metals such as scandium and iron to almost inert elements, such as the platinum metals. Transition metals exhibit chemical behavior typical of metals. The type of chemistry used in the isolation of the elements from their ores depends upon the concentration of the element in its ore and the difficulty of reducing ions of the elements to the metals.

Key terms

transition metals: elements with partially filled d orbitals, located in the d -block of the periodic table
platinum metals: group of six transition metals consisting of ruthenium, osmium, rhodium, iridium, palladium, and platinum that tend to occur in the same minerals and demonstrate similar chemical…
cis configuration: configuration of a geometrical isomer in which two similar groups are on the same side of an imaginary reference line on the molecule
e g orbitals: set of two d orbitals that are oriented on the Cartesian axes for coordination complexes; in octahedral complexes, they are higher in energy than the t 2 g orbitals
f -block element: (also, inner transition element) one of the elements with atomic numbers 58-71 or 90-103 that have valence electrons in f orbitals; they are frequently shown offset below the…
geometric isomers: isomers that differ in the way in which atoms are oriented in space relative to each other, leading to different physical and chemical properties
hydrometallurgy: process in which a metal is separated from a mixture by first converting it into soluble ions, extracting the ions, and then reducing the ions to precipitate the pure metal
ionization isomer: (or coordination isomer) isomer in which an anionic ligand is replaced by the counter ion in the inner coordination sphere

Chapter 20

Organic Chemistry

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Summary

The alkanes are saturated hydrocarbons—that is, hydrocarbons that contain only single bonds. The chemistry of these compounds is called organic chemistry. Hydrocarbons are organic compounds composed of only carbon and hydrogen. Alkenes contain one or more carbon-carbon double bonds.

Key terms

alkanes: saturated hydrocarbons—that is, hydrocarbons that contain only single bonds
aromatic hydrocarbon: cyclic molecule consisting of carbon and hydrogen with delocalized alternating carbon-carbon single and double bonds, resulting in enhanced stability
alkene: molecule consisting of carbon and hydrogen containing at least one carbon-carbon double bond
alkyne: molecule consisting of carbon and hydrogen containing at least one carbon-carbon triple bond
saturated hydrocarbon: molecule containing carbon and hydrogen that has only single bonds between carbon atoms
alkane: molecule consisting of only carbon and hydrogen atoms connected by single (σ) bonds
organic compound: natural or synthetic compound that contains carbon
chemistry of these compounds: called organic chemistry

Chapter 21

Nuclear Chemistry

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Summary

This “missing” mass is the mass defect, which has been converted into the binding energy that holds the nucleus together according to Einstein’s mass-energy equivalence equation, E = mc 2 . Although protons repel each other, the nucleus is held tightly together by a short-range, but very strong, force called the strong nuclear force. An atomic nucleus consists of protons and neutrons, collectively called nucleons. A nucleus has less mass than the total mass of its constituent nucleons.

Key terms

nuclear chemistry: study of the structure of atomic nuclei and processes that change nuclear structure
mass defect: difference between the mass of an atom and the summed mass of its constituent subatomic particles (or the mass “lost” when nucleons are brought together to form a nucleus)
magic number: nuclei with specific numbers of nucleons that are within the band of stability
mass-energy equivalence equation: Albert Einstein’s relationship showing that mass and energy are equivalent
band of stability: (also, belt of stability, zone of stability, or valley of stability) region of graph of number of protons versus number of neutrons containing stable (nonradioactive) nuclides
nucleus: held tightly together by a short-range, but very strong, force called the strong nuclear force
binding energy per nucleon: total binding energy for the nucleus divided by the number of nucleons in the nucleus
strong nuclear force: force of attraction between nucleons that holds a nucleus together