Question

An element X (atomic number 17) reacts with an element Y (atomic number 20) to form a divalent halide.

What will be the nature of oxide of element Y? Identify the nature of bonding in the compound formed.

Answer 1

Nature of oxide of element Y and nature of bonding:
Element Y i.e.; Calcium $\left(\mathrm{Ca}\right)$ with atomic number 20, is a metal that forms an oxide that is basic in nature.

• The atomic number of Calcium= $20$
• Electronic configuration of Calcium=$2,8,8,2$
• This is because these metal oxides react with water to form a base.

As one of the elements is metal i.e.; calcium and the other is non-metal i.e.; Oxygen (for the oxide of element Y), electrons are lost and gained by them respectively as shown below.

• The atomic number of Oxygen= $8$
• Electronic configuration of Oxygen= $2,6$

$\underset{\left(\mathrm{Calcium}\right)}{\mathrm{Ca}}\to \underset{(\mathrm{Calcium}\mathrm{ion})}{{\mathrm{Ca}}^{+2}}+\underset{\left(\mathrm{Electrons}\right)}{2{\mathrm{e}}^{-}}$

$\underset{\left(\mathrm{Oxygen}\right)}{\mathrm{O}}+\underset{\left(\mathrm{Electrons}\right)}{2{\mathrm{e}}^{-}}\to \underset{(\mathrm{Oxide}\mathrm{ion})}{{\mathrm{O}}^{-2}}$

• This results in the formation of the ions and the bond formed between the ions are known as an ionic bond.
• So, the nature of the bond will be an ionic bond in the oxide i.e.; Calcium oxide$\left(\mathrm{CaO}\right)$.