Question

A metal M forms an ionic compound X of formula M2(So4)3 ( 2 and 3 subscript)
a) write the cation formula in the X .
b)what is the formula of nitrate of metal' M' ?

Answer 1

Answer :

(a) The cation formula in the compound X $(M_2(SO_4)_3)$ will be, $M^{3+}$

(b) The formula of nitrate of metal 'M' is $M(NO_3)_3$.

Explanation :

For formation of a neutral ionic compound, the charges on cation and anion must be balanced.

The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

In the given question, the metal forms an ionic compound with polyatomic anion $SO_4^{2-}$ with the formula $M_2(SO_4)_3$. As the valencies of ions are crossed while writing the formula, that means the valency of metal is +3.

Part (a) :

Thus, the cation formula in the compound X $(M_2(SO_4)_3)$ will be, $M^{3+}$ and the anion formula in the compound X $(M_2(SO_4)_3)$ will be, $SO_4^{2-}$

Part (b) :

As per question, when the metal (M) with valency of +3 combines with nitrate $NO_3^-$ to form compound metal nitrate $M(NO_3)_3$.

Thus, the formula of nitrate of metal 'M' is $M(NO_3)_3$.

Answer 2

To write the formula of a binary molecular compound, first use the prefixes in the name to tell you the subscript of each element in the formula. Then, write the correct symbols for the two elements with the appropriate subscripts.