Potasio (K): Bohr Model, Protons, Neutrons & Electrons
Potasio is element number 19, an alkali metal in group 1, period 4. Its atom has 19 protons, 20 neutrons and 19 electrons arranged in 4 shells: 2, 8, 8, 1.
- 19 protons
- 20 neutrons
- 19 electrons
Protons, neutrons and electrons in potassium
El atomic number of potassium is 19, so every potassium atom has 19 protons. A neutral atom has the same number of electrons, 19. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For potassium-39, that is 39 − 19 = 20 neutrons. Potassium has 2 stable isotopes, with 20, 22 neutrons.
How to draw the Bohr model of potassium
- Draw the nucleus and write 19 p⁺ y 20 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 8 electrons on it.
- Draw the fourth shell and put 1 electron on it.
- Check: 2 + 8 + 8 + 1 = 19 electrons, the same as the number of protons.
Electron configuration
The electron configuration of potassium is [Ar] 4s¹. Its 1 outer electron decides how it reacts: it tends to lose it, forming K⁺ ions.
Key facts about potassium
| Symbol | K |
|---|---|
| Atomic number | 19 |
| Relative atomic mass | 39.098 |
| Group · period · block | group 1 · period 4 · s-block |
| Tipo | Metal alcalino |
| State at 25 °C | solid |
| Capas electrónicas | 2, 8, 8, 1 |
| Electron configuration | [Ar] 4s¹ |
| Electrones de valencia | 1 |
| Common ion | K⁺ |
| Electronegativity (Pauling) | 0.82 |
| First ionisation energy | 4.34 eV (419 kJ/mol) |
| Atomic radius (empirical) | 220 pm |
¿Dónde potassium sits on the periodic table
Preguntas frecuentes
How many protons, neutrons and electrons does potassium have?
Potassium has 19 protons and 19 electrons (atomic number 19). Its most common isotope, potassium-39, has 39 − 19 = 20 neutrons.
What is the electron configuration of potassium?
[Ar] 4s¹. In shells that is 2, 8, 8, 1.
How many valence electrons does potassium have?
1. Potassium is in group 1, and its outer shell holds 1 electron.
Where is potassium on the periodic table?
In group 1, period 4, in the s-block. It is an alkali metal.
