Hydrogen (H)
Hydrogen makes up roughly three quarters of all ordinary matter in the universe by mass.
Hydrogen properties
- Atomic mass
- 1.008 u
- Category
- Reactive nonmetal
- Group
- 1
- Period
- 1
- Block
- s-block
- Melting point
- 13.99 K (-259.2 °C)
- Boiling point
- 20.27 K (-252.9 °C)
- Density
- 0.09 g/L
- Common charges
- +1, −1
- Oxidation states
- +1, −1
- Atomic radius
- 120 pm
- Ionization energy
- 13.598 eV
- Electron affinity
- 0.754 eV
- Radioactive
- No, has stable isotopes
- Discovered
- 1766
Hydrogen electron configuration
- Full electron configuration
- 1s1
- Electron shells
- 1
The electron configuration of Hydrogen (H) is 1s1. Its 1 electrons are arranged in shells as 1.
Protons, neutrons and electrons in Hydrogen
A neutral Hydrogen atom has 1 protons and 1 electrons. Most Hydrogen atoms have about 0 neutrons: the atomic mass rounded to 1, minus the atomic number 1.
Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass
How many valence electrons does Hydrogen have?
1
Hydrogen has 1 valence electron in its outermost shell, shell 1. These are the electrons involved in chemical bonding.
Hydrogen orbital diagram
Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations
Molar mass of Hydrogen
1.008 g/mol
One mole of Hydrogen atoms (6.022 × 10²³ atoms) has a mass of 1.008 grams. Use this value to convert between grams and moles.
Compounds containing Hydrogen
Hydrogen facts
- Hydrogen makes up roughly three quarters of all ordinary matter in the universe by mass.
- A hydrogen atom has no neutron in its most common form — just one proton and one electron.
- Hydrogen (H) has atomic number 1 and is a gas at room temperature. It was discovered in 1766.
Position in the periodic table
Hydrogen is element 1, in period 1 and group 1 of the periodic table, in the s-block.
Uses of Hydrogen
Hydrogen is used mainly to make ammonia for fertilizers and to remove sulfur from fuels in oil refineries. It is also used to make methanol and to harden vegetable oils into spreads such as margarine. Fuel cells combine hydrogen with oxygen to generate electricity, with water as the only product, and liquid hydrogen fueled rockets such as the Space Shuttle's main engines.
Who discovered Hydrogen?
English scientist Henry Cavendish identified hydrogen as a distinct substance in 1766, producing it by reacting metals with acids and calling it 'inflammable air'. Antoine Lavoisier later named it hydrogen, meaning 'water-former', after showing that it burns to make water.
Where does the name come from?
Hydrogen comes from the Greek words hydro, 'water', and genes, 'forming', so it means 'water-former'. Antoine Lavoisier coined the name in French (hydrogène) in the 1780s after showing that burning hydrogen produces water.
Same group
Compare Hydrogen
FAQ
What is the electron configuration of Hydrogen?
The electron configuration of Hydrogen (H) is 1s1. Its 1 electrons are arranged in shells as 1.
How many protons, neutrons and electrons does Hydrogen have?
A neutral Hydrogen atom has 1 protons and 1 electrons. Most Hydrogen atoms have about 0 neutrons: the atomic mass rounded to 1, minus the atomic number 1.
How many valence electrons does Hydrogen have?
Hydrogen has 1 valence electron in its outermost shell, shell 1. These are the electrons involved in chemical bonding.
What is the molar mass of Hydrogen?
The molar mass of Hydrogen is 1.008 g/mol. This is the same number as its atomic mass, 1.008 u.
Is Hydrogen a metal?
No. Hydrogen is a reactive nonmetal, so it is a nonmetal.
Is Hydrogen radioactive?
Ordinary Hydrogen is not radioactive: it has at least one stable isotope. Like every element, it also has radioactive isotopes, most of them made in laboratories.
Where is Hydrogen on the periodic table?
Hydrogen is element 1, in period 1 and group 1 of the periodic table, in the s-block.