Metallic bonds are: A. bonds holding together atoms with very different
electronegativities.
B. bonds holding together a metal and a nonmetal.
C. bonds holding together two atoms of different kinds of metal.
D. bonds holding together two atoms of the same kind of metal.

D. bonds holding together two atoms of the same kind of metal.

Explanation:

Metallic bonds are very special kinds of interatomic forces that holds metals together and confers such unique properties on them.

The formation of this bond type is favored by large atomic radius, low ionization energy and a large number of electrons in the valence shell.

the answer is 75.0%.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)