Criptón (Kr): Bohr Model, Protons, Neutrons & Electrons
Criptón is element number 36, a noble gas in group 18, period 4. Its atom has 36 protons, 48 neutrons and 36 electrons arranged in 4 shells: 2, 8, 18, 8.
- 36 protons
- 48 neutrons
- 36 electrons
Protons, neutrons and electrons in krypton
El atomic number of krypton is 36, so every krypton atom has 36 protons. A neutral atom has the same number of electrons, 36. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For krypton-84, that is 84 − 36 = 48 neutrons. Krypton has 6 stable isotopes, with 42, 44, 46, 47, 48, 50 neutrons.
How to draw the Bohr model of krypton
- Draw the nucleus and write 36 p⁺ y 48 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 8 electrons on it.
- Check: 2 + 8 + 18 + 8 = 36 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, 8) is the one to draw.
Electron configuration
The electron configuration of krypton is [Ar] 4s² 3d¹⁰ 4p⁶. Its 8 outer electrons decide how it reacts: its outer shell is full, so it hardly reacts at all.
Key facts about krypton
| Symbol | Kr |
|---|---|
| Atomic number | 36 |
| Relative atomic mass | 83.798 |
| Group · period · block | group 18 · period 4 · p-block |
| Tipo | Gas noble |
| State at 25 °C | gas |
| Capas electrónicas | 2, 8, 18, 8 |
| Electron configuration | [Ar] 4s² 3d¹⁰ 4p⁶ |
| Electrones de valencia | 8 |
| Common ion | none: its outer shell is already full |
| Electronegativity (Pauling) | 3.00 |
| First ionisation energy | 14.00 eV (1351 kJ/mol) |
| Atomic radius (empirical) | — |
¿Dónde krypton sits on the periodic table
Preguntas frecuentes
How many protons, neutrons and electrons does krypton have?
Krypton has 36 protons and 36 electrons (atomic number 36). Its most common isotope, krypton-84, has 84 − 36 = 48 neutrons.
What is the electron configuration of krypton?
[Ar] 4s² 3d¹⁰ 4p⁶. In shells that is 2, 8, 18, 8.
How many valence electrons does krypton have?
8. Krypton is in group 18, and its outer shell holds 8 electrons.
Where is krypton on the periodic table?
In group 18, period 4, in the p-block. It is a noble gas.
