Xenón (Xe): Bohr Model, Protons, Neutrons & Electrons
Xenón is element number 54, a noble gas in group 18, period 5. Its atom has 54 protons, 78 neutrons and 54 electrons arranged in 5 shells: 2, 8, 18, 18, 8.
- 54 protons
- 78 neutrons
- 54 electrons
Protons, neutrons and electrons in xenon
El atomic number of xenon is 54, so every xenon atom has 54 protons. A neutral atom has the same number of electrons, 54. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For xenon-132, that is 132 − 54 = 78 neutrons. Xenon has 9 stable isotopes, with 70, 72, 74, 75, 76, 77, 78, 80, 82 neutrons.
How to draw the Bohr model of xenon
- Draw the nucleus and write 54 p⁺ y 78 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 18 electrons on it.
- Draw the fifth shell and put 8 electrons on it.
- Check: 2 + 8 + 18 + 18 + 8 = 54 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, 18, 8) is the one to draw.
Electron configuration
The electron configuration of xenon is [Kr] 5s² 4d¹⁰ 5p⁶. Its 8 outer electrons decide how it reacts: its outer shell is full, so it hardly reacts at all.
Key facts about xenon
| Symbol | Xe |
|---|---|
| Atomic number | 54 |
| Relative atomic mass | 131.29 |
| Group · period · block | group 18 · period 5 · p-block |
| Tipo | Gas noble |
| State at 25 °C | gas |
| Capas electrónicas | 2, 8, 18, 18, 8 |
| Electron configuration | [Kr] 5s² 4d¹⁰ 5p⁶ |
| Electrones de valencia | 8 |
| Common ion | none: its outer shell is already full |
| Electronegativity (Pauling) | 2.60 |
| First ionisation energy | 12.13 eV (1170 kJ/mol) |
| Atomic radius (empirical) | — |
¿Dónde xenon sits on the periodic table
Preguntas frecuentes
How many protons, neutrons and electrons does xenon have?
Xenon has 54 protons and 54 electrons (atomic number 54). Its most common isotope, xenon-132, has 132 − 54 = 78 neutrons.
What is the electron configuration of xenon?
[Kr] 5s² 4d¹⁰ 5p⁶. In shells that is 2, 8, 18, 18, 8.
How many valence electrons does xenon have?
8. Xenon is in group 18, and its outer shell holds 8 electrons.
Where is xenon on the periodic table?
In group 18, period 5, in the p-block. It is a noble gas.
