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 are correct.

Question

Quizplus · Accepted Answer

As the oxidation number on the metal increases, the valence-state electronegativity increases and the oxides tend to become more basic. However, when the oxidation state of the metal is high enough, the oxide starts to become acidic. This is because the electron density on the oxide becomes more negative, making it a better proton acceptor and therefore more acidic. This is the case for oxides of chromium and manganese. So, the oxides of chromium and manganese change from basic to acidic as the oxidation number on the metal increases.

Chromium and Manganese Are Among the Transition Elements That Form