Name the elements in Period 1.

What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 3 ?

If an element is in Group 17 [or Group 7A] is it likely to be metallic or non-metallic in character ?

Supply the missing word from those in brackets: If an element has one electron in it's outermost energy level [shell] then it is likely to be …………… [metallic / non- metallic].