Question

The number of electron pairs around a central atom can be established from

Answer 1

Electron pairs are arranged evenly around the central atom and are in the same plane as the central atom. Electron pairs are arranged around the central atom such that they are located at the four corners of a tetrahedron.

I hope that helps a little

Answer 2

It's STERIC NUMBER.

Step-by-step explanation:

The steric number is the number of shared pairs of electrons on a central atom of a molecule (σ sigma bond) plus the number of lone pairs on the central atom.