Question

The correct statements among I to III regarding group 13 elements oxides are:
(I) Boron trioxide is acidic.
(II) Oxides of aluminium and gallium are amphoteric.
(III) Oxides of indium and thallium are basic.
(A) (I), (II) and (III)
(B) II) and (III) only
(C) (I) and (III) only
(D) (I) and (II) only

Answer 1

When we go down the group, the non-metallic character will decrease and the metallic character will increase in group 13 elements. Also, the acidic character of oxides formed from group 13 elements will decrease down the group and the basic character will increase. The reactivity of group 13 elements towards oxygen to form the corresponding oxides increases down the group.

Complete step by step solution:
- As we know, the periodic table is categorized into s, p, d and f blocks. The group thirteen elements are the first group in the p-block elements of the periodic table and all the elements of group 13 are also known as the boron family. The elements in group 13 are boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).
- The electronic configuration for group 13 elements is $n{{s}^{2}}n{{p}^{1}}$. All of the group 13 elements will give sesquioxides (which means one and a half) and the oxide can be represented by the formula ${{M}_{2}}{{O}_{3}}$ where M is the corresponding group 13 element.
- The first element boron acts a non-metal and hence the oxide formed from boron that is ${{B}_{2}}{{O}_{3}}$ or boron trioxide will be acidic in nature. Hence the statement (I) is correct.
- The elements aluminium and gallium act as amphoteric which means that they can dissolve both in acids and bases. Therefore the oxides of these elements $A{{l}_{2}}{{O}_{3}}$ and $G{{a}_{2}}{{O}_{3}}$ are amphoteric in nature. Thus the statement (II) is also correct.
- The elements indium and thallium are both metals and they will form the oxides $I{{n}_{2}}{{O}_{3}}$ and $T{{I}_{2}}{{O}_{3}}$ which are both basic in nature. Hence the statement (III) is also correct.

Therefore the answer is option (A). All the statements (I), (II) and (III) are correct.

Note: Keep in mind that the element boron behaves differently from the rest of the group 13 elements and it’s due to the following reasons. Boron has a very small size and it has very high ionization energy. Also, boron has high electronegativity owing to its small size and the d-orbital in the valence shell are absent.