Zinc (Zn): Bohr Model, Protons, Neutrons & Electrons
Zinc is element number 30, a transition metal in group 12, period 4. Its atom has 30 protons, 34 neutrons and 30 electrons arranged in 4 shells: 2, 8, 18, 2.
Protons, neutrons and electrons in zinc
The atomic number of zinc is 30, so every zinc atom has 30 protons. A neutral atom has the same number of electrons, 30. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For zinc-64, that is 64 − 30 = 34 neutrons. Zinc has 5 stable isotopes, with 34, 36, 37, 38, 40 neutrons.
How to draw the Bohr model of zinc
- Draw the nucleus and write 30 p⁺ and 34 n⁰ inside it.
- Draw the first shell and put 2 electrons on it (the first shell holds at most 2).
- Draw the second shell and put 8 electrons on it.
- Draw the third shell and put 18 electrons on it.
- Draw the fourth shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 2 = 30 electrons, the same as the number of protons.
From potassium onwards the shells don’t simply fill as 2, 8, 8: the fourth shell starts before the third is full, so the real arrangement above (2, 8, 18, 2) is the one to draw.
Electron configuration
The electron configuration of zinc is [Ar] 4s² 3d¹⁰. As a transition metal it fills an inner d-subshell, and its common ion is Zn²⁺.
Key facts about zinc
| Symbol | Zn |
|---|---|
| Atomic number | 30 |
| Relative atomic mass | 65.38 |
| Group · period · block | group 12 · period 4 · d-block |
| Type | Transition Metal |
| State at 25 °C | solid |
| Electron shells | 2, 8, 18, 2 |
| Electron configuration | [Ar] 4s² 3d¹⁰ |
| Valence electrons | varies (outer shell: 2) |
| Common ion | Zn²⁺ |
| Electronegativity (Pauling) | 1.65 |
| First ionisation energy | 9.39 eV (906 kJ/mol) |
| Atomic radius (empirical) | 135 pm |
Where zinc sits on the periodic table
Frequently asked questions
How many protons, neutrons and electrons does zinc have?
Zinc has 30 protons and 30 electrons (atomic number 30). Its most common isotope, zinc-64, has 64 − 30 = 34 neutrons.
What is the electron configuration of zinc?
[Ar] 4s² 3d¹⁰. In shells that is 2, 8, 18, 2.
How many valence electrons does zinc have?
Zinc is a transition metal, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is zinc on the periodic table?
In group 12, period 4, in the d-block. It is a transition metal.
