Element 8 of Periodic table is Oxygen with atomic number 8, atomic weight 15.9994. Oxygen, symbol O, has a Base Centered Monoclinic structure and Colorless color. Oxygen is a other nonmetal element. Trivial name of Oxygen is chalcogens*. Know everything about Oxygen Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms compounds (notably oxides) with most elements. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.
Read key information and facts about element Oxygen
| Name | Oxygen |
| Atomic Number | 8 |
| Atomic Symbol | O |
| Atomic Weight | 15.9994 |
| Phase | Gas |
| Color | Colorless |
| Classification | other nonmetal |
| Group in Periodic Table | 16 |
| Group Name | oxygen family |
| Period in Periodic Table | 2 |
| Block in Periodic Table | p-block |
| Electronic Configuration | [He] 2s2 2p4 |
| Melting Point | -218.3 °C |
| Boiling Point | -182.9 °C |
| Electronic Shell Structure | [2, 6] |
| CAS Number | CAS7782-44-7 |
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 8 to find Oxygen on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Oxygen on periodic table look for cross section of group 16 and period 2 in the modern periodic table.
The element Oxygen was discovered by Carl Wilhelm Scheele in year 1774 in Sweden and United Kingdom . Oxygen derived its name from the Greek word oxy-, both 'sharp' and 'acid', and -gen, meaning 'acid-forming'
The table below shows the abundance of Oxygen in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
| Ppb by weight (1ppb =10^-7 %) | |
|---|---|
| Abundance in Universe | 0.01 |
| Abundance in Sun | 0.009 |
| Abundance in Meteorites | 0.4 |
| Abundance in Earth's Crust | 0.46 |
| Abundance in Oceans | 0.86 |
| Abundance in Humans | 0.61 |
The solid state structure of Oxygen is Base Centered Monoclinic.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
| a | b | c |
|---|---|---|
| 540.3 | 342.9 | 508.6 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
| alpha | beta | gamma |
|---|---|---|
| π/2 | 2.313085 | π/2 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
| Space Group Name | C12/m1 |
|
| Space Group Number | 12 | |
| Crystal Structure | Base Centered Monoclinic |
Oxygen atoms have 8 electrons and the electronic shell structure is [2, 6] with Atomic Term Symbol (Quantum Numbers) 3P2.
| Atomic Number | 8 |
| Number of Electrons (with no charge) | 8 |
| Number of Protons | 8 |
| Mass Number | 16 |
| Number of Neutrons | 8 |
| Shell structure (Electrons per energy level) | [2, 6] |
| Electron Configuration | [He] 2s2 2p4 |
| Valence Electrons | 2s2 2p4 |
| Oxidation State |
-2;-1
1;2 |
| Atomic Term Symbol (Quantum Numbers) | 3P2 |
Shell Structure of Oxygen - Electrons per energy level
| n | s | p | d | f | |
|---|---|---|---|---|---|
| 1 | K | 2 | |||
| 2 | L | 2 | 4 |
The ground state electronic configuration of Neutral Oxygen atom is [He] 2s2 2p4. The portion of Oxygen configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [He]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used.This is important as it is the Valence electrons 2s2 2p4, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Oxygen atom, Unabbreviated electronic configuration
1s2 2s2 2p4
Oxygen atomic radius is 48 pm, while it's covalent radius is 73 pm.
| Atomic Radius |
48 pm (0.48 Å) |
| Atomic Volume | 11.1962211337 cm3 |
| Covalent Radius | 73 pm (0.73 Å) |
| Van der Waals Radius | 152 pm |
| Neutron Cross Section | 0.00028 σa/barns |
The electron affinity of Oxygen is 141 kJ/mol
| Valence | 2 |
| Electronegativity | 3.44 |
| ElectronAffinity | 141 kJ/mol |
Refer to table below for Ionization energies of Oxygen
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1 | 1313.9 |
| 2 | 3388.3 |
| 3 | 5300.5 |
| 4 | 7469.2 |
| 5 | 10989.5 |
| 6 | 13326.5 |
| 7 | 71330 |
| 8 | 84078 |
Refer to below table for Oxygen Physical Properties
| Density | 1.429 g/l |
| Molar Volume | 11.1962211337 cm3 |
| Young Modulus | N/A |
| Shear Modulus | N/A |
| Bulk Modulus | N/A |
| Poisson Ratio | N/A |
| Mohs Hardness | N/A |
| Vickers Hardness | N/A |
| Brinell Hardness | N/A |
Oxygen is N/A of electricity. Refer to table below for the Electrical properties of Oxygen
| Electrical Conductivity | N/A |
| Resistivity | N/A |
| Superconducting Point | N/A |
| Thermal Conductivity | 0.02658 W/(m K) |
| Thermal Expansion | N/A |
| Magnetic Type | Paramagnetic |
| Curie Point | N/A |
| Mass Magnetic Susceptibility | 1.335×10-6 |
| Molar Magnetic Susceptibility | 4.27184×10-8 |
| Volume Magnetic Susceptibility | 1.90772×10-6 |
| Refractive Index | 1.000271 |
| Speed of Sound | 317.5 m/s |
Refer to table below for Thermal properties of Oxygen
| Melting Point | 54.8 K (-218.3 °C) |
| Boiling Point | 90.2 K (-182.9 °C) |
| Critical Temperature | 154.59 K |
| Superconducting Point | N/A |
| Heat of Fusion | 0.222 kJ/mol |
| Heat of Vaporization | 3.41 kJ/mol |
| Heat of Combustion | N/A |
Isotopes of rhodium. Naturally occurring Oxygen has 3 stable isotope - 16O, 17O, 18O.
| Isotope | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|
| 12O | ||||
| 13O | ||||
| 14O | ||||
| 15O | ||||
| 16O | 99.757% | Stable | N/A | |
| 17O | 0.038% | Stable | N/A | |
| 18O | 0.205% | Stable | N/A | |
| 19O | ||||
| 20O | ||||
| 21O | ||||
| 22O | ||||
| 23O | ||||
| 24O | ||||
| 25O | ||||
| 26O | ||||
| 27O | ||||
| 28O |
| CAS Number | CAS7782-44-7 |
| RTECS Number | RTECSRS2060000 |
| DOT Hazard Class | 2.2 |
| DOT Numbers | 1073 |
| EU Number | N/A |
| NFPA Fire Rating | 0 |
| NFPA Hazards | Oxidizing Agent |
| NFPA Health Rating | 3 |
| NFPA Reactivity Rating | 2 |
| Autoignition Point | N/A |
| Flashpoint | N/A |
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7782-44-7 |
| CID Number | CID977 |
| Gmelin Number | N/A |
| NSC Number | N/A |
| RTECS Number | RTECSRS2060000 |
Metalloid |
Nonmetals |
| Other Nonmetals | |
| Halogens | Noble Gas |
Metals |
|
| Alkali Metals | Alkaline Earth Metals |
| Transition Metals | Post-Transition Metals |
| Lanthanide | Actinide |