Answer:
1
Name Calcium
Atomic Mass 40.078 atomic mass units
Number of Protons 20
Number of Neutrons 20
Number of Electrons 20
2 Iodine is element number 53. Iodine has 53 protons and 53 electrons (because it has no charge the number of protons equals the number of electrons). Iodine-131 has 131 protons and neutrons.
3 Name Lead
Atomic Mass 207.2 atomic mass units
Number of Protons 82
Number of Neutrons 125
Number of Electrons 82
