Explain the following:

Ionic compounds dissolve in water whereas covalent compound do not.

Explain the following:

Ionic compounds are usually hard crystals.

Five atoms are labelled from $\mathrm{A}$ to $\mathrm{E}$.

(a) Which one of these atoms:(i) contains $7$ protons (ii) has an electronic configuration $2,7$?

(b) Write down the formula of the compound between $\mathrm{C}$ and $\mathrm{D}$.

(c) Predict which are: (i) metals (ii)non-metals.

What is the difference between ionic compounds and polar covalent compounds?

What is the difference between ionic compounds and covalent compounds.

What is the difference between a polar covalent compound and a non-polar covalent compound.

Match the atomic number $4, 14, 8, 15$ and $19$ with the following:

A solid non-metal of valency $3$.

Match the atomic number $4, 14, 8, 15$ and $19$ with the following:

A gas of valency $2$.

Match the atomic number $4, 14, 8, 15$ and $19$ with the following:

A metal of valency $1$