Number of compounds with one lone pair of electrons on central atom amongst following is _______O3,H2O,SF4,ClF3,NH3,BrF5,XeF4

To answer this question, we need to look at the Lewis structures of each compound to determine the number of lone pairs on the central atom.

1. O3 (Ozone): The central atom is O, which has one lone pair of electrons.
2. H2O (Water): The central atom is O, which has two lone pairs of electrons.
3. SF4 (Sulfur tetrafluoride): The central atom is S, which has one lone pair of electrons.
4. ClF3 (Chlorine trifluoride): The central atom is Cl, which has two lone pairs of electrons.
5. NH3 (Ammonia): The central atom is N, which has one lone pair of electrons.
6. BrF5 (Bromine pentafluoride): The central atom is Br, which has one lone pair of electrons.
7. XeF4 (Xenon hexafluoride): The central atom is Xe, which has two lone pairs of electrons.

So, the number of compounds with one lone pair of electrons on the central atom amongst the following is 4 (O3, SF4, NH3, BrF5).