Which is most likely to form a negative ion?

A. An element from group 17

B. A metal

C. An element from group 1

D. An element with atoms that have eight valence electrons

A

Explanation:

In other options, they form positive ion as they have extra electrons in their valence shell

But in group 17, all the elements have 7 electrons in their valence shell, inorder to attain octet they require one more electron

Hence, they form negative ion by gaining electron

A

Explanation:

An element from group 17 wants to gain an electron to from a negative ion. A metal forms only positive ions, an element from group 1 will lose to form a positive ion and elements with eight valence electrons are normally very stable, meaning they don't need to lose or gain.