Which one of the following compounds is a Lewis acid?

What change occurs in the electronic configuration of atoms forming a covalent bond?

Who gave the concept of a covalent bond? What is a covalent bond? Explain with one example.

How many electrons are shared between atoms in a double bond?

The bonds between $P$ atoms and $Cl$ atoms in $PCl_5$ are likely to be

The $X-X$ bond length is $1.00 \mathring{A}$ and $C-C$ bond length is $1.54 \mathring{A}$. If $EN$ of $X$ and $C$ are $3.0$ and $2.0$ respectively,the $C-X$ bond length is likely to be ............ $\mathring{A}$.