Number of Lone Pairs on the Central Atom in XeOF4

To determine the number of lone pairs on the central atom in XeOF4, we need to consider the electron arrangement and the hybridization of the central atom.

1. Electron Arrangement:
The electron arrangement of xenon (Xe) in XeOF4 can be determined using the concept of the octet rule. Xenon has an atomic number of 54, which means it has 54 electrons. The fluorine (F) atoms each contribute one electron, totaling four electrons. The oxygen (O) atom contributes six electrons. Therefore, the total number of electrons in XeOF4 is:

54 (Xe) + 4 (F) + 6 (O) = 64 electrons

2. Hybridization:
To determine the hybridization of the central atom, we need to count the number of regions of electron density around the central atom. This includes both bonding and lone pairs of electrons.

In XeOF4, the xenon atom is bonded to one oxygen atom and four fluorine atoms. This gives us a total of five regions of electron density around the central atom.

The electron arrangement and hybridization of xenon can be determined using the following guidelines:
- 2 regions of electron density: sp hybridization
- 3 regions of electron density: sp2 hybridization
- 4 regions of electron density: sp3 hybridization
- 5 regions of electron density: sp3d hybridization

In the case of XeOF4, there are five regions of electron density around the central xenon atom. Therefore, the xenon atom in XeOF4 is sp3d hybridized.

3. Lone Pairs:
In sp3d hybridization, there are five hybrid orbitals formed, which are directed towards the corners of a trigonal bipyramid. Four of these orbitals are used for bonding with the surrounding atoms (oxygen and fluorine), leaving one hybrid orbital with a lone pair of electrons on the central xenon atom.

Therefore, the number of lone pairs on the central atom in XeOF4 is 1.

In conclusion, XeOF4 has 1 lone pair on the central xenon atom due to its sp3d hybridization.