Oxygen properties
- Atomic mass
- 15.999 u
- Category
- Reactive nonmetal
- Group
- 16
- Period
- 2
- Block
- p-block
- Electronegativity
- 3.44
- Melting point
- 54.36 K (-218.8 °C)
- Boiling point
- 90.19 K (-183 °C)
- Density
- 1.429 g/L
- Atomic radius
- 152 pm
- Ionization energy
- 13.618 eV
- Electron affinity
- 1.461 eV
- Radioactive
- No, has stable isotopes
- Discovered
- 1774
Oxygen electron configuration
- Electron configuration
- [He] 2s2 2p4
- Full electron configuration
- 1s2 2s2 2p4
- Electron shells
- 2 · 6
The electron configuration of Oxygen (O) is [He] 2s2 2p4. Its 8 electrons are arranged in shells as 2, 6.
Protons, neutrons and electrons in Oxygen
A neutral Oxygen atom has 8 protons and 8 electrons. Most Oxygen atoms have about 8 neutrons: the atomic mass rounded to 16, minus the atomic number 8.
Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass
How many valence electrons does Oxygen have?
6
Oxygen has 6 valence electrons in its outermost shell, shell 2. These are the electrons involved in chemical bonding.
Oxygen 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 Oxygen
15.999 g/mol
One mole of Oxygen atoms (6.022 × 10²³ atoms) has a mass of 15.999 grams. Use this value to convert between grams and moles.
Compounds containing Oxygen
Oxygen facts
- Oxygen is the most abundant element in Earth's crust by mass.
- Liquid oxygen is pale blue and is attracted to a magnet.
- Oxygen (O) has atomic number 8 and is a gas at room temperature. It was discovered in 1774.
Position in the periodic table
Oxygen is element 8, in period 2 and group 16 of the periodic table, in the p-block.
Uses of Oxygen
Oxygen is used in huge amounts in steelmaking, where it is blown through molten iron to burn off carbon and other impurities. Hospitals supply oxygen to patients who have trouble breathing, and welders burn acetylene in pure oxygen to cut and join metal. Liquid oxygen serves as the oxidizer in many rocket engines, and oxygen is also used to treat wastewater and make chemicals.
Who discovered Oxygen?
Joseph Priestley discovered oxygen in 1774 in England by focusing sunlight on mercury(II) oxide and collecting the gas it released. Carl Wilhelm Scheele had made it independently a little earlier but published later, and Antoine Lavoisier gave oxygen its name.
Where does the name come from?
Oxygen comes from the Greek oxys, 'sharp' or 'acid', and genes, 'forming', so it means 'acid-former'. Antoine Lavoisier chose the name because he mistakenly believed that all acids contain oxygen.
Same group
Compare Oxygen
FAQ
What is the electron configuration of Oxygen?
The electron configuration of Oxygen (O) is [He] 2s2 2p4. Its 8 electrons are arranged in shells as 2, 6.
How many protons, neutrons and electrons does Oxygen have?
A neutral Oxygen atom has 8 protons and 8 electrons. Most Oxygen atoms have about 8 neutrons: the atomic mass rounded to 16, minus the atomic number 8.
How many valence electrons does Oxygen have?
Oxygen has 6 valence electrons in its outermost shell, shell 2. These are the electrons involved in chemical bonding.
What is the molar mass of Oxygen?
The molar mass of Oxygen is 15.999 g/mol. This is the same number as its atomic mass, 15.999 u.
Is Oxygen a metal?
No. Oxygen is a reactive nonmetal, so it is a nonmetal.
Is Oxygen radioactive?
Ordinary Oxygen 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 Oxygen on the periodic table?
Oxygen is element 8, in period 2 and group 16 of the periodic table, in the p-block.