Which of the following observations indicate an atom has neutrons

Rutherford postulated the existence of some neutral particle having mass similar to proton but there was no direct experimental evidence. Several theories and experimental observations eventually led the discovery of neutron.

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.