Answer:
The one with the greatest mass would be the one that has the most things in the nucleus, protons and nutrons
Explanation:
1.T
2.F
3.T
I think I think Im not complety sure sorry
Answer:
number of valence electrons
Explanation:
All of the elements in group 17, also known as group 7A, have 7 valence electrons.
No two elements have the same atomic number nor atomic mass in elemental form.
Halogens may have any number of isotopes.
