Question

Find # of protons, neutrons, total electrons, valence electrons and core electron of CO3 2-

Answer 1

Carbon, neutral state is 6 p+, 6 e-, and 6 n, mass = 12.01 amu. Oxygen neutral state is 8 p+, 8 e- and 8 n, mass = 16 amu.
The ion in question has one carbon and 3 oxygen, nuclear material remains unchanged, so we can just tally it all up. and get total p+ of (3*8 +6) = 30, with matching counts on n and e- is 2+ that from the total charge of -2, for 32 e-. core electron count is 2 for each atom as they all start with 1s2/1px, giving us 6 core electrons, which when we deduct from the 32 total e- gives us 24 valence e-.