Reading symbolic descriptions of atoms
Determine the number of protons and neutrons in each of the following nuclei: { }_3^6 \mathrm{Li},{ }_8^{16} \mathrm{O},{ }_{13}^{27} \mathrm{Al},{ }_{26}^{56} \mathrm{Fe},{ }_{30}^{64} \mathrm{Zn} \text {, and }{ }_{47}^{107} \mathrm{Ag} .
Sketch and translate For lithium Z = 3, so it has three protons in the nucleus. Lithium has A = 6 nucleons; thus there are three neutrons (N = 3).
Simplify and diagram We use the same strategy to determine the number of protons (Z) and the number of neutrons 1N2 in the other elements and summarize the results in the table below:
Try it yourself: Determine Z and N for potassium-39, { }_{19}^{39} \mathrm{~K} \text {. }
Answer: Z = 19 and N = 20.
\pmb{ { }_3^6 \mathrm{Li} } | \pmb{{ }_8^{16} \mathrm{O} } | \pmb{{ }_{13}^{27} \mathrm{Al} } | \pmb{{ }_{26}^{56} \mathrm{Fe} } | \pmb{{ }_{30}^{64} \mathrm{Zn} } | \pmb{{ }_{47}^{107} \mathrm{Ag} } |
Z N | Z N | Z N | Z N | Z N | Z N |
3 3 | 8 8 | 13 14 | 26 30 | 30 34 | 47 60 |