Why sncl2 is solid but sncl4 is liquid at room temperature

Stannous(IV) chloride is a substance of molecular structure, so it is a liquid and volatile. Stannous(II) chloride is a substance of a crystal structure, therefore, is in the solid state at room temperature.

Yes it would be a physical change.

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.