What is the geometry of the central carbon atom of a tert-butyl radical?

Trigonal planar

Trigonal planar is a molecular geometry that results when there are three bonds and no lone pairs around the central atom in the molecule. The pairs are arranged along the central atoms equator with 120 degrees angle between them. Molecules with this geometry have sp2d hybridization at the central atom. The central carbon atom of a tert-butyl radical has this type of geometry.

 

It will fall off and tip over. 

Non metal is an element or substance that is not a metal metal is a solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivitymetalloid is an element (e.g., germanium or silicon) whose properties are intermediate between those of metals and solid nonmetals. they are electrical semiconductors.