Question

Compound of a metal ‘M’ is ${M_2}{O_3}$. What would be the formula of its nitride?
A) ${M_3}N$
B) $MN$
C) ${M_3}{N_2}$
D) ${M_2}{N_3}$

Answer 1

As we know that various metals react with oxygen to form metal oxides and they possess more or less a similar valency as the oxygen atom to form a stable metal oxide. So to form a nitride, a metal should possess a similar valency as the nitride to form metal nitride.

Complete step by step solution:
As we are already aware that the metals react with oxygen forming a metal oxide. The metal in the given metal oxide possess a valency of $+ 3$ and oxygen possess a valency of $- 2$ and when they react with each other their valencies will get exchanged and this is how the metal oxide is formed as ${M_2}{O_3}$.
Similarly we can form its nitride because we know that nitride possesses a valency of $- 3$ and we are already aware of the valency of metal which is $+ 3$. So after the exchange of their valencies, the nitride so formed will be ${M_3}{N_3}$ or we can simply write it as $MN$.

Therefore, from the above explanation we can say that the correct answer is (B).

Additional information: We can also find out the metal name as the given metal has $+ 3$valency so it means the metal belongs to group $13$ of the periodic table and we know that Aluminium possess $+ 3$ valency thus the metal oxide formed is $A{l_2}{O_3}$ and the metal nitride is $AlN$.

Note: Always remember that the valency which is basically the number of atoms present in the outermost shell of an atom or we can say that it is the capacity of an atom to react particular atom or elements and valency of a positive atom is exchanged with the valency of negative atom resulting in a stable compound formed.