What is an ion? what is a valence electron? how is an ion formed?

Ions are formed when atoms lose or gain electrons in order to fulfill the octet rule and have full outer valence electron shells. When they lose electrons, they become positively charged and are named cations. When they gain electrons, they are negatively charged and are named anions.

Explanation:

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.