Question

Which of the following substances has covalent bonding
A) Germanium
B) Sodium chloride
C) Solid neon
D) Copper

Answer 1

Hint: The element or atom which tries to get the noble gas configuration by sharing electron pairs form covalent bonds. Especially non metals form covalent bonds.

Complete step by step solution:Sodium chloride has the molecular formula of $NaCl$ . Here sodium has one electron and chlorine has seven electrons in its valence shell. Sodium is a metal. So, it removes its electron and chlorine accepts the electron. Thus ionic bonds are formed.
Solid neon has an ionic bond between its atoms.
Copper is a transition metal. Pure metal metal bond is present between copper.
Germanium is a group fourteen element.
The general electronic configuration of the element germanium is \[n{{s}^{2}}n{{p}^{2}}\].Thus it contains two electrons in the ns sub shell and two electrons in the np sub shell. Thus it need electrons to complete its octet. Due to high ionization energy germanium cannot remove electron easily. Again it can’t gain electrons due to strong force of attraction towards the electrons from nucleus. To form bond with any other atom germanium shares its electron and makes a strong covalent bond. That’s why germanium shares its electrons to form covalent bond.

Amongst the given substances covalent bonding is found in germanium.

Thus the correct option is A.

Note: Germanium is a metalloid. It has the properties between the metals and non metals. Germanium cannot exist as an ion. Its electrons are never free. It is highly conductive and malleable.