Hello Gaurav,

Some of the properties of ionic compounds are:

• Ionic Compounds have high boiling points and melting points. They are very strong and require a lot of energy to break.
• Ionic compounds can form crystals.
• The electrostatic force of attraction between oppositely charged ions leads to the formation of ions.
• Ionic compounds cannot conduct electricity in the solid state, but they can conduct electricity in the molten state.

Some of the properties of covalent compounds are:

• Covalent compounds have low  boiling points  and melting points.
• Covalent compounds  have bonds where electrons are shared between atoms.
• Covalent compounds have various colors.
• Covalent compounds are poor conductors of heat and electricity.
• Covalent compounds are brittle solids.

There are only three allotropes of Group 16 elements. They are- Oxygen, Sulfur, and Selenium. Each of them displays allotropy. Oxygen has two allotropes, which are- Oxygen (O2) and Ozone (O3). Sulphur exists as many allotropic forms but the stable ones are- Rhombic Sulphur and Monoclinic Sulphur. Selenium and Tellurium are found in both amorphous and crystalline forms.

Hope this helps!!!