In the structure of ClF₃, the number of lone pair of electrons on central atom ‘Cl’ is:

Concept:

Calculation of number of lone pairs on central meta atom-

• Lone pair is pair of electrons on an atom that do not participate in the bonding.
• The number of lone pairs on an atom is given by -
  • Number of lone pairs on an atom = \(\frac{Total \hspace {0.1cm} number\hspace {0.1cm} of \hspace {0.1cm}valence\hspace {0.1cm} electron\hspace {0.1cm} on \hspace {0.1cm}the \hspace {0.1cm}atom\hspace {0.1cm} -\hspace {0.1cm} electrons \hspace {0.1cm}participate\hspace {0.1cm} in\hspace {0.1cm} bond\hspace {0.1cm} formation}{2}\)
• The presence of lone pair can easily be visualized in the shape of a molecule as they affect the orientation of bonding electrons through a lone pair-lone pair or lone pair-bond pair repulsion. 

Explanation:

In the structure of ClF₃, the central metal is Cl. We have to calculate the number of lone pairs present on Cl.

• So, the atomic number of Cl is 17  and its electronic configuration is [Ne] 3s² 3p⁵.
• The total number of valence electrons of Cl is 7.
• In ClF3, three fluorine atoms are bonded to Cl. So, the number of shares or bonded electron sin Cl is 3.

According to the formula - Number of lone pairs on an atom = \(\frac{Total \hspace {0.1cm} number\hspace {0.1cm} of \hspace {0.1cm}valence\hspace {0.1cm} electron\hspace {0.1cm} on \hspace {0.1cm}the \hspace {0.1cm}atom\hspace {0.1cm} -\hspace {0.1cm} electrons \hspace {0.1cm}participate\hspace {0.1cm} in\hspace {0.1cm} bond\hspace {0.1cm} formation}{2}\)

So, the number of lone pairs on Cl = \(\frac{7-3}{2}\),

= 4/2 = 2

The total number of lone pairs on Cl is = 2.

The geometry of ClF₃ will be Trigonal Bipyramidal and due to the presence of 2 lone pairs shapes, it will be T-Shape.

∴ The number of lone pairs of electrons on central Cl is 2.

Hence, the correct answer is option 2.