Question

Element X is a metal with a valency 2, Y is a non-metal with a valency 3. If Y is a diatomic gas, write an equation for the direct combination of X and Y to form a compound.

Answer 1

Hint: We have to create anion and cation first.
Cross multiply the valency to get a compound.
Write metal and non-metal in their natural state.
Write equations using elements in natural state as reactant and final compound as products.

Complete step by step answer:
Since element X is metal, it will form cation by giving 2 electrons, as valency is 2.
\[X \to {X^{2 + }} + 2{e^ - }\]
Since element Y is non-metal, it will form anion by accepting 3 electrons, as valency is 3.
\[Y + 3{e^ - } \to {Y^{3 - }}\]
Since we know valency so we will cross multiply valency to get compound, \[{X_3}{Y_2}\]
Since X is metal so it will be monatomic, and Y is diatomic gas so natural state will be \[{Y_2}\]
Thus overall equation is:
\[3X + {Y_2} \to {X_3}{Y_2}\]\[\]

Additional information: The metals will donate electrons to form cation and nonmetals will accept electrons to form anion. The compound formed from the combination of cation and anion is an ionic compound.

Note:
Generally one may forget to balance the equation, but it is necessary to balance the equation. There might be common errors that one may consider valency to be the number of atoms in a compound, but we should cross multiply valency for getting ionic compounds.