What did Henry Moseley contribute to the modern periodic table? O A. He discovered the lanthanides and actinides.
O B. He identified all of the elements that are currently in the periodic
table.
O C. He ordered the elements based on atomic number.
O D. He ordered the elements based on atomic mass.

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.