Answer to Question #158658 in General Chemistry for teeeeeeeera

Question

These are the first two ionization energies for potassium:

     K (g) -------> K^+ (g) + e^- (g) Ionization energy = 418.8 kJ/mol

     K^+(g) -----> K^2 (g) + e (g) Ionization energy = 3052.0 kJ/mol

a) Explain the large increase in ionization energy that occurs for the removal of the second electron.

(Select all that apply.)

-The second electron is removed from the positively charged ion.

-The removal of the second electron fills the valence shell.

-The second electron is farther from the nucleus.

-The second electron is removed from the lower principal energy level.

b) The radius of K^+ is 138 pm (1 pm =10^-12m) while that of a potassium atom, K, is 227 pm. Explain why the radius of K^+ is so much smaller than the radius of K.

(Select all that apply.)

-On the lower principal energy level, the outermost orbital is much smaller and the electron's attraction to the nucleus is stronger in K^+.

-The nucleus of an ion is smaller than the nucleus of an atom.

-With the loss of a valence electron from K, the positive charge in the nucleus exceeds the collective negative charge of the electrons thus decreasing the atomic radius.

-The second electron has higher energy than the first electron.

Answer 1

a. -The removal of the second electron fills the valence shell.

-The second electron is removed from the positively charged ion.

-The second electron is removed from the lower principal energy level.

b. -On the lower principal energy level, the outermost orbital is much smaller and the electron's attraction to the nucleus is stronger in K^+.

With the loss of a valence electron from K, the positive charge in the nucleus exceeds the collective negative charge of the electrons thus decreasing the atomic radius.