Hydrogen (H): Bohr Model, Protons, Neutrons & Electrons
Hydrogen is element number 1, a nonmetal in group 1, period 1. Its atom has 1 protons, 0 neutrons and 1 electrons arranged in 1 shell: 1.
Protons, neutrons and electrons in hydrogen
The atomic number of hydrogen is 1, so every hydrogen atom has 1 protons. A neutral atom has the same number of electrons, 1. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For hydrogen-1, that is 1 − 1 = 0 neutrons. Hydrogen has 2 stable isotopes, with 0, 1 neutrons.
How to draw the Bohr model of hydrogen
- Draw the nucleus and write 1 p⁺ and 0 n⁰ inside it.
- Draw the first shell and put 1 electron on it (the first shell holds at most 2).
- Check: 1 = 1 electrons, the same as the number of protons.
Electron configuration
The electron configuration of hydrogen is 1s¹. Its 1 outer electron decides how it reacts: it tends to lose it, forming H⁺ ions.
Key facts about hydrogen
| Symbol | H |
|---|---|
| Atomic number | 1 |
| Relative atomic mass | 1.008 |
| Group · period · block | group 1 · period 1 · s-block |
| Type | Nonmetal |
| State at 25 °C | gas |
| Electron shells | 1 |
| Electron configuration | 1s¹ |
| Valence electrons | 1 |
| Common ion | H⁺ |
| Electronegativity (Pauling) | 2.20 |
| First ionisation energy | 13.60 eV (1312 kJ/mol) |
| Atomic radius (empirical) | 25 pm |
Where hydrogen sits on the periodic table
Frequently asked questions
How many protons, neutrons and electrons does hydrogen have?
Hydrogen has 1 protons and 1 electrons (atomic number 1). Its most common isotope, hydrogen-1, has 1 − 1 = 0 neutrons.
What is the electron configuration of hydrogen?
1s¹. In shells that is 1.
How many valence electrons does hydrogen have?
1. Hydrogen is in group 1, and its outer shell holds 1 electron.
Where is hydrogen on the periodic table?
In group 1, period 1, in the s-block. It is a nonmetal.
