Number of lone pairs of electrons in the central atom of SCl2, O3, CIF3 and SF6, respectively are:

To determine the number of lone pairs on the central atom, we need to draw the Lewis structure for each molecule and count the number of lone pairs on the central atom.

1. SCl2: The central atom is Sulfur (S). Sulfur has 6 valence electrons, and it forms two bonds with two Chlorine atoms. This leaves 4 electrons, which form 2 lone pairs. So, SCl2 has 2 lone pairs on the central atom.

2. O3: The central atom is Oxygen (O). In the Lewis structure of O3, the central Oxygen atom forms double bonds with the other two Oxygen atoms, leaving no lone pairs on the central atom. So, O3 has 0 lone pairs on the central atom.

3. ClF3: The central atom is Chlorine (Cl). Chlorine has 7 valence electrons. It forms three bonds with three Fluorine atoms, leaving 1 lone pair. So, ClF3 has 1 lone pair on the central atom.

4. SF6: The central atom is Sulfur (S). Sulfur has 6 valence electrons, and it forms six bonds with six Fluorine atoms. This leaves no lone pairs on the central atom. So, SF6 has 0 lone pairs on the central atom.

So, the number of lone pairs of electrons in the central atom of SCl2, O3, ClF3, and SF6 are 2, 0, 1, and 0, respectively.