Why do metallic bonds form a compound with a sea of electrons?

Question

Metal atoms are bonded with other metal atoms because the electrons are simultaneously transferred to the nuclei and held in rigid structures.

Metal atoms are bonded with nonmetal atoms because the electrons are simultaneously transferred to the nuclei and held in rigid structures. 

The electrons are shared by all the nuclei because the electrons are not strongly attracted to the atoms’ nuclei and therefore move around freely between the metal atoms.

Metal atoms are bonded with nonmetal atoms because the electrons are shared with all the metal and nonmetal nuclei to reach the octet rule. 

Answer 1

You can think of a bond is a couple of OVER-SIMPLIFIED ways.

One way is by transferring an electron. Then one partner becomes positive, the other negative, and the coulombic attraction ( + and - attract each other) keeps the 2 partners together.

A SIMPLIFIED way to think of a covalent bond is that two (or more) electrons are shared - spending part of the time with one atom, part of the time with the other. We say the electrons are "localized" between the 2 atom cores (nuclei), and this keeps the atoms in the bond together.

Metal atoms typically want to give up electrons. When they are with a lot of other metal atoms - they all want to give up their electrons. And they do. We describe this situation as nuclei ( the positively charged "cores" of the metal atoms) in a "sea of electrons" because the electrons are just swimming around between ALL the cores - and not bound to any one or 2 metal cores in the substance. Since they are not bound, we say they are NOT localized - like we would have in a covalent bond. The electrons are roaming freely throughout the whole substance. Like they are swimming in a sea, with lot of other electrons.

This is an important clue as to why metals are good conductors. When we apply a potential, we can get all those electrons moving all in the same direction. This is a crude picture of electric current,