A. Atoms, Ions, and Molecules

Question 1

Differentiate atomic number (Z), mass number (A), isotopes, nuclide?

Answer 1

Z - number of proton/electron (if neutral)
A - no. of proton + neutron
isotopes - same atomic number different mass number (same element, different no. of neutrons)
nuclide - nucleus of specific isotopes

Question 2

Common isotopes of hydrogen

Answer 2

H-1: protium
H-2: deuterium
H-3: tritium