Respuesta :
Answer:
Because the non-metal comes from the right hand side of the Periodic Table as we face it, its nuclear charge is very poorly shielded by its INCOMPLETE valence electronic shell, and this results in the well-known contraction of atomic radii across the Table from left to right.
Explanation:
Non metals usually gain electrons so they have more electron in the shells than protons in nucleus and hence they form negative ions. However, metals usually lose electron so they have more protons in nucleus than electrons in shells and hence they form positive ions.