1.atom 2.energy level 3.atomic number 4.compound 5.shell 6.electrons 7.molecule 8.atomic mass 9.neutrons 10.diatonic 11.proton
I think it's A to be honest i think it is A
The atomic number is 49.
The atomic number is the same as the number of protons. So if there are 49 protons, then the atomic number of element A is 49.
