How can two atoms that have the same amount of protons and mass, but one has different charges? how is there atomic structure different, and what does it have to do with atomic particles?

The answer is: two atoms have same number of protons and neutrons, but different number of electrons.

Mass number (A) is the total number of protons and neutrons in a nucleus.

Atomic mass (ma) is approximately equivalent to the number of protons and neutrons in the atom.

For example, chlorine atom (Cl) and chlorine anion (Cl⁻).

Similarities:

1) atomic number is the same. Both, chlorine atom and anion, have atomic number 17. They have 17 protons in nucleus of an atom.

2) both are the same element.

Difference:  

1) chlorine atom (Cl) has neutral change and chlorine anion (chloride ion Cl⁻) has negative charge, because chlorine anion has one electron more.

explanation:

0.07 g/cm³

1.37 g/cm³