Respuesta :

It can form a covalent bond with a hydrogen bond that has one valence electron to have eight valence electrons and become stable.

Answer: The element needs to react with other element by gaining an electron to complete its valence electron.

Explanation: The element which exhibit 7 valence electrons are halogens. They readily react with other element, for example: Hydrogen and Sodium, in order to gain an electron to complete their outermost shell.