Question

The element that does NOT form acidic oxide is

• A. Carbon
• B. Phosphorus
• C. Chlorine
• D. Barium

Answer 1

Answer: (D)

The acidic oxides are formed by the non-metals (group 14-17) whereas basic oxides are formed by the metals of group 1 and group 2 elements.
As the atoms get larger, the ionisation energy decreases and the elements also become more basic. $BeO$ is an amphoteric oxide, $MgO$ is weakly basic while $BaO$ is highly basic oxide.