Question
Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides?
A.
$$A{l_2}{O_3} < MgO < N{a_2}O < {K_2}O$$
B.
$$MgO < {K_2}O < A{l_2}{O_3} < N{a_2}O$$
C.
$$N{a_2}O < {K_2}O < MgO < A{l_2}{O_3}$$
D.
$${K_2}O < N{a_2}O < A{l_2}{O_3} < MgO$$
Answer :
$$A{l_2}{O_3} < MgO < N{a_2}O < {K_2}O$$
Solution :
On moving across a period ionisation energy increases hence the electropositive nature of metals decreases therefore the ease of formation of ion also decreases and hence the basic character decreases. Further basic
character ofalkali metals oxides increases from $$L{i_2}O$$ to
$$C{s_2}O.$$ Hence the correct order will be $$A{l_2}{O_3} < MgO < N{a_2}O < {K_2}O$$