Chromium and manganese are among the transition elements that form several different oxides. Which of the following statements characterize these oxides?
A) As the oxidation number on the metal increases, the valence-state electronegativity increases and the oxides change from acidic to basic.
B) As the oxidation number on the metal increases, the valence-state electronegativity increases and the oxides change from basic to acidic.
C) As the oxidation number on the metal increases, the valence-state electronegativity decreases and the oxides change from acidic to basic.
D) As the oxidation number on the metal increases, the valence-state electronegativity decreases and the oxides change from basic to acidic.
E) None of these choices is correct.

Question

Quizplus · Accepted Answer

As the oxidation number on the metal increases, the valence-state electronegativity increases and the oxides become more basic. This is because the metal cation becomes more polarizing, which means it has a stronger attraction for electrons in the oxide ion. As a result, the oxide ion becomes more basic, and the oxide as a whole becomes more basic. When the oxidation number increases further, the valence-state electronegativity continues to increase, making the oxide even more basic. However, eventually, the oxide becomes so basic that it reacts with water to form an acidic solution. Therefore, as the oxidation number on the metal increases, the oxides change from basic to acidic.

Chromium and Manganese Are Among the Transition Elements That Form