Question

in a sample of which of these elements would you expect to find a sea of electrons surrounding nuclei?
he
ag
na
n

Explanation:

A "sea of electrons" is a characteristic of metallic bonding, found in metals. He (helium) is a noble gas (non-metal), As (arsenic) is a metalloid, N (nitrogen) is a non-metal, and Na (sodium) is an alkali metal. Only metals exhibit metallic bonding with delocalized electrons forming a "sea" around nuclei.

Answer:

Na (assuming the option labeled "Nu" is a typo for Na, as Na is the correct metallic element here)