7. atoms gain and lose electrons to get a outer nrg level.

what goes in the blank?

Explanation: Atoms gain or lose electrons to get a full outermost energy level.

Atoms want to be happy and they can achieve that by the octet rule. It states that 2 atoms can go in the first shell and after that 8 can go in the second shell and so on. Atoms want to have a full outer shell of 8 electrons unless their the elements with fewer protons like hydrogen and helium since they will need 2 electrons to satisfy the octet rule.

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