Chapter EH, Problem 13R

Solution

Interpretation : The general trend in first ionization energies in group 2 is to be described and explained.

Concept Introduction : Ionization energy is the bare minimum of energy that an electron in a gaseous atom or ion needs absorb to escape from the nucleus. The elements of group 2 have two valence electrons.

The first ionization energies in group 2 elements usually decrease down the group.

The elements of group 2 include beryllium, magnesium, calcium, strontium, barium, and radon.

The group 2 elements are also called alkaline earth metals.

The ionization energy usually decreases down the group.

The atomic number rises and the number of shells rises as a group moves downward.

Outermost electrons can be easily removed because they are far from the nucleus.

Moving down a group, the shielding effect brought on by an expanding number of shells is the second reason that lowers the ionization energy.