Chapter 7.4, Problem 7.6.1PE

Consider the following statements about first ionization energies:

1. Because the effective nuclear charge for Mg is greater than that for Be, the first ionization energy of Mg is greater than that of Be.
2. The first ionization energy of 0 is less than that of N because in Owe must pair electrons in one of the 2p orbitals.
3. The first ionization energy of Ar is less than that of Ne because a 3p electron in Ar is farther from the nucleus than a 2p electron in Ne.

Which of the statements (i), (ii), and (iii) is or are true?

1. Only one of the statements is true.
2. Statements (i) and (ii) are true.
3. Statements (i) and (iii) are true.
4. Statements (ii) and (iii) are true.
5. All three statements are true.