Question

which groups of elements are metals and which are nonmetals.

Answer 1

The non-metals or non-metallic elements; hydrogen (H), carbon (C), nitrogen (N), oxygen (O), phosphorus (P), sulphur (sulfer) (S), selenium (Se), (Uuo may belong here) and the noble gases form a relatively small group with a step like pattern towards the left-hand side of the periodic table (hydrogen being the odd one out on the right of the table). Non-metals are not strictly defined, but tend to show characteristic properties like poor heat and electrical conductivity, form acidic oxides, dull low lustre and brittle, low densities, low melting points and high electro negativity.

Hydrogen can become metallic when exposed to extremely high pressures. Some allotropes of elements show more pronounced metal, metalloid or non-metal behaviour than others. The element carbon; its diamond allotrope is non-metallic, however the graphite allotrope is electrically conductive showing characteristic more like a metalloid. Phosphorus, and selenium also have allotropes which display borderline behaviour.

I hope it help you please mark brain list