SolutionsConstitution
1. Protons, neutrons and electrons
State how many protons, neutrons and electrons the atoms 6Li, 7Li and 23Na have (atomic numbers: Li = 3, Na = 11).
| Atom | Protons | Neutrons | Electrons |
|---|---|---|---|
| 6Li | 3 | 3 | 3 |
| 7Li | 3 | 4 | 3 |
| 23Na | 11 | 12 | 11 |
The isotopes of an element differ only in the number of neutrons.
2. How many electrons fit?
What is the maximum number of electrons in shell 2? And in shell 3?
Shell 2: 2 (s) + 6 (p) = 8. Shell 3: 2 (s) + 6 (p) + 10 (d) = 18.
3. Quantum numbers
Write the possible quantum numbers of an electron in a 2p orbital.
N = 2; L = 1; M = −1, 0 or +1 (the three p orbitals); S = +½ or −½.