8. Is 4.5 in the
figure a known or an
estimated digit?

Iwould you figure it out but you don't have a picture or in your question as to what the physical property you're looking for is

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.