Question

What is the general valence-electron ground-state electron configuration for neutral alkaline earth metals? A) ns2 B) 1s22s2 C) 1s22s1 D) ns1

Answer 1

A) `"ns"^2"`, where `"n=2-7"`, corresponding to the highest energy level available, as indicated by the period number.

For the main group elements, groups 1, 2, 13-18, the valence electrons are in the outermost s and p sublevels. The alkaline metals are in group 2, which means they have 2 valence electrons in their outermost s sublevel.

The ground state electron configurations for the six alkaline earth metals in group 2 are:

Period 2, Be:`"1s"^2"2s"^2`
Period 3, Mg:`["Ne"]3"s"^2`
Period 4, Ca:`["Ar"]4"s"^2`
Period 5, Sr:`["Kr"]5"s"^2`
Period 6, Ba:`["Xe"]6"s"^2`
Period 7, Ra:`["Rn"]7"s"^2`