Exercise

$\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ are three elements with atomic number $6, 11$ and $17$ respectively.

Which of these can form ionic as well as covalent bonds? 

An element A has an atomic number of 6. Another element B has 17 electrons in its one neutral atom. What type of bond is formed between A and B? [Covalent bond / Ionic Bond]

Valence bond theory was proposed by_____.

Represent the molecule ${\mathrm{H}}_2\mathrm{O}$ by using Lewis notation.

Write Lewis dot structures for $\mathrm{S}$ and ${\mathrm{S}}^{2-}$.

Two chemical reactions are described below.

(i) Nitrogen and hydrogen react to form ammonia $\left({\mathrm{NH}}_3\right)$.

(ii) Carbon and hydrogen bond to form a molecule of methane $\left({\mathrm{CH}}_4\right)$.

For each reaction give the valency of each of the atoms involved in the reaction. 

Explain the formation of water molecule.

The bond present in $\mathrm{HCl}$ molecule is _____.