Hi,
Homogeneous mixture 2
Heterogeneous 3
Mixture 1
Solution 5
Compound 4
Any element in group 18 has eight valence electrons (except for helium, which has a total of just two electrons). Examples include neon (Ne), argon (Ar), and krypton (Kr). Oxygen, like all the other elements in group 16, has six valence electrons.
By adding together the number of protons and neutrons and multiplying by 1 amu, you can calculate the mass of the atom.
The answer should be B. hope this helped ;)
