Question

The correct decreasing order of basic character of oxides is:

• A. $K_{2}O>MgO>SrO>C{s}_{2}O$
• B. $C{s}_{2}O>K_{2}O>SrO>MgO$
• C. $MgO>SrO>K_{2}O>C{s}_{2}O$
• D. $C{s}_{2}O>K_{2}O>MgO>SrO$

Answer 1

The correct option is B $C{s}_{2}O>K_{2}O>SrO>MgO$

Option $\left(B\right)$ is correct.

The correct decreasing order of basic character of oxides $C{s}_{2}O>K_{2}O>SrO>MgO$

Oxides of alkali metals are more reactive than alkaline metal and basic character of oxides of both alkali and alkaline metal increases down the group from atomic radius increases so ionisation energy decrease, this means that tendency of losing electron increases which implies an increase in metallic character ( as electron affinity also decreases ). We know that oxides of metals are basic in nature. Thus basic character increases down the group from $L{i}_{2}O$ to $C{s}_{2}O$ and from $MgO$ to $BaO$. While $BeO$ is amphoteric in nature.