Chapter 4, Problem 4.6P

Interpretation Introduction

Interpretation:

In gas phase, the energy that is required to convert $6.022\times {10}^{23}$ neutral helium atoms into ${\text{He}}^{\text{2+}}$ ions in gas phase has to be calculated.

Concept Introduction:

Ionization energy is the minimum amount of energy that is required to remove a valence electron from a neutral atom in gaseous atom or ion.  In the periodic table a trend is present for the ionization energy across the period and down the group.  Ionization energy increases across the period as electrons are added to the same orbital and there is an increase in effective nuclear charge.  Ionization energy decreases down the Group as electrons are added to next orbital.

First ionization energy is the energy that is required to remove one valence electron from an atom $\text{A}$ to form a positively charge gaseous ion ${\text{(A}}^{\text{+}}\text{)}$.  Second ionization energy is the amount of energy that is required to remove an electron from gaseous ion ${\text{(A}}^{\text{+}}\text{)}$ to form ${\text{(A}}^{\text{2+}}\text{)}$ ion.