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.

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.