Polonium (Po): Bohr Model, Protons, Neutrons & Electrons
Polonium is element number 84, a post-transition metal in group 16, period 6. Its atom has 84 protons, 125 neutrons and 84 electrons arranged in 6 shells: 2, 8, 18, 32, 18, 6.
Protons, neutrons and electrons in polonium
The atomic number of polonium is 84, so every polonium atom has 84 protons. A neutral atom has the same number of electrons, 84. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For polonium-209, that is 209 − 84 = 125 neutrons. Every isotope of polonium is radioactive; 209 is the mass number of its most stable one.
How to draw the Bohr model of polonium
- Draw the nucleus and write 84 p⁺ and 125 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 32 electrons on it.
- Draw the fifth shell and put 18 electrons on it.
- Draw the sixth shell and put 6 electrons on it.
- Check: 2 + 8 + 18 + 32 + 18 + 6 = 84 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, 32, 18, 6) is the one to draw.
Electron configuration
The electron configuration of polonium is [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p⁴. Its 6 outer electrons decide how it reacts: it tends to lose them, forming Po²⁺ ions.
Key facts about polonium
| Symbol | Po |
|---|---|
| Atomic number | 84 |
| Relative atomic mass | [209] |
| Group · period · block | group 16 · period 6 · p-block |
| Type | Post-transition Metal |
| State at 25 °C | solid |
| Electron shells | 2, 8, 18, 32, 18, 6 |
| Electron configuration | [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p⁴ |
| Valence electrons | 6 |
| Common ion | Po²⁺ |
| Electronegativity (Pauling) | 2.00 |
| First ionisation energy | 8.41 eV (811 kJ/mol) |
| Atomic radius (empirical) | 190 pm |
Where polonium sits on the periodic table
Frequently asked questions
How many protons, neutrons and electrons does polonium have?
Polonium has 84 protons and 84 electrons (atomic number 84). Its most common isotope, polonium-209, has 209 − 84 = 125 neutrons.
What is the electron configuration of polonium?
[Xe] 6s² 4f¹⁴ 5d¹⁰ 6p⁴. In shells that is 2, 8, 18, 32, 18, 6.
How many valence electrons does polonium have?
6. Polonium is in group 16, and its outer shell holds 6 electrons.
Where is polonium on the periodic table?
In group 16, period 6, in the p-block. It is a post-transition metal.
