SolutionsTwo Electrons
1. What will happen to beryllium?
Beryllium (Z = 4) has the configuration 1s2 2s2. How can it reach the configuration of helium?
By giving up its two 2s electrons: it becomes the Be2+ ion, with a complete shell 1, like helium.
2. Li and Li+
Why is the Li+ ion much smaller than the lithium atom?
When the 2s electron is lost, shell 2 disappears, and the three protons of the nucleus attract the two remaining electrons of shell 1 more strongly.