Question

(a) write the symbols/formulae of two simple ions and two compound ions (or polyatomic ions).
(b) an element Y has a valency of 4. Write the formula for its:
(i) chloride (ii) oxide (iii) sulphate (iv) carbonate (v) nitrate

Answer 1

(a) Simple ion is formed due to gain or loss of electrons by a single atom of an element, For eg. Na^$+$, K^$+$, Mg^$+$2, etc.
A compound ion is formed due to excess anions or cations in a compound. For eg. ammonium ions (NH₄^$+$), carbonate ions(CO₃^$-$2), etc.

(b) (i) As Y has four valence electrons, it will form four single bonds with a chlorine atom and form YCl_4.
(ii) As Y has four valence electrons, it will form two double bonds with an oxygen atom and form YO_2.
(iii) As Y has four valence electrons, it will form two double bonds with sulfate atom and form Y(SO₃)_2.
(iv) As Y has four valence electrons, it will form two double bonds with carbonate and form Y(CO₃)₂.
(v) As Y has four valence electrons, it will form four single bonds with nitrate and form Y(NO₃)₄.