Electron geometry of the central atom br in brf4+

Octahedral

Explanation:

Recall that according to Valence Shell Electron Pair Repulsion Theory(VSEPR) the shape of a molecule is based on the number of electron pairs on the outermost shell of its central atom.

In BrF4^-, the bromine atom is surrounded by 6 electron pairs. Four bond pairs and two lone pairs.  This means a total of six regions of electron density.

According to VSEPR Theory,  BrF4^- has an octahedral electron geometry and its the molecular geometry will be square planar  since it is of the type AX4E2.

An image of the  BrF4^- is attached below.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.