Question

Is the F-F bond strong?

Answer 1

Fluorine is a very electronegative element, and has a very small size. For bond to be strong, repulsion from electrons must be minimum.

Complete step-by-step answer: In order to answer our question, we need to learn about covalent bond. The loss or gain of electrons is not allowed take place between similar atoms. In such cases the bond formed by mutual sharing of electrons. A force which puts atoms of different or same elements together by mutual sharing of electrons is known as a covalent bond.
The atoms involved in bond formations contribute equal number of electrons for sharing. The shared electrons are common to both of the atoms and includes a bond between them. The shared pair of electrons which is needed for forming or creating the bond is called bond pair of electrons. Let us consider the formation of Cl, molecule, this will help us in better understanding of the Lewis-Langmuir theory.
Each chlorine atom, $[Ne]3{{s}^{2}}3{{p}^{5}}$ has seven electrons in its valence-shell and needs one more electron to acquire octet or to attain the electronic configuration of Argon. Both the chlorine atoms contribute one electron each to share two electrons (shared pair). The bond can be represented by putting a line (-) between the atoms or with electron dot symbols also.
Now, the bond order in ${{F}_{2}}$ molecule is 0.6, which makes the F-F bond weaker than the Cl-Cl bond. It is due to the fact that the fluorine molecule experiences repulsion, due to lone pair and has a small size.

Note: The valence electrons not involved in sharing are known as non-bonding electrons or lone pairs or unshared to as Lewis dot structures. The pairs. Each chlorine atom has 3 lone pairs.