Atomic No Of Oxygen

  1. Atomic No Number Of Oxygen
  2. Atomic No Of Oxygen Used

Oxygen is a colourless, odourless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air. It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is a chemical element with atomic number 8 which means there are 8 protons and 8 electrons in the atomic structure. The chemical symbol for Oxygen is O. Oxygen is a colourless, odourless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air.

  • Formula: O
  • Molecular weight: 15.9994
  • IUPAC Standard InChI:
    • InChI=1S/O
    • Download the identifier in a file.
  • CAS Registry Number: 17778-80-2
  • Chemical structure:
    This structure is also available as a 2d Mol file
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Gas phase ion energetics data

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Data compilation copyrightby the U.S. Secretary of Commerce on behalf of the U.S.A.All rights reserved.

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

IE (evaluated)13.61806eVN/AN/AL
Proton affinity (review)485.2kJ/molN/AHunter and Lias, 1998HL
Gas basicity459.6kJ/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV)MethodReferenceComment
1.439157 ± 0.000004LPDJoiner, Mohr, et al., 2011Given: 11607.75(28) cm-1. In 1.0 T field, 0.5 kcal/mol lower than 'best' EA; B
1.4610 ± 0.0010LPESCavanagh, Gibson, et al., 2007B
1.460982 ± 0.000044LPDBlondel, Chaibi, et al., 2005(16)O: 1.4611135(12) eV: revised analysis of Blondel, Delsart, et al., 2001; B
1.461112 ± 0.000044LPDNeumark, Lykke, et al., 1985Given: 1.461122(3) eV; revised to 1.4611107(17) eV, 95BLO, based on missing term+86CODATA; B
1.461112 ± 0.000044N/AValli, Blondel, et al., 199916O: 11784.682(20) cm-1; 18O: 11784.612(29) cm-1 or 8.7μeV lower.; B

Ionization energy determinations

IE (eV)MethodReferenceComment
13.61806EVALLide, 1992LL
13.618SKelly, 1987LBLHLM
13.0 ± 0.5EIBanon, Chatillon, et al., 1982LBLHLM
13.618PIRadler and Berkowitz, 1977LLK
14. ± 1.EIPaule, 1976LLK
14.0 ± 0.5EIHildenbrand, 1975LLK
13.618SCermak, 1975LLK
13.61806SMoore, 1970RDSH
13.62PEJonathan, Morris, et al., 1970RDSH

Anion protonation reactions

O- + =

By formula: O- + H+ = HO

Δr1600.798 ± 0.042kJ/molD-EANeumark, Lykke, et al., 1985gas phase; Given: 1.461122(3) eV; revised to 1.4611107(17) eV, 95BLO, based on missing term+86CODATA; B
Δr1576.2 ± 0.63kJ/molH-TSNeumark, Lykke, et al., 1985gas phase; Given: 1.461122(3) eV; revised to 1.4611107(17) eV, 95BLO, based on missing term+86CODATA; B


Go To:Top, Gas phase ion energetics data, Notes

Data compilation copyrightby the U.S. Secretary of Commerce on behalf of the U.S.A.All rights reserved.

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G.,Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update,J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, [all data]

Atomic No Number Of Oxygen

Joiner, Mohr, et al., 2011
Joiner, A.; Mohr, R.H.; Yukich, J.N.,High-resolution photodetachment spectroscopy from the lowest threshold of O-,Phys. Rev. A, 2011, 83, 3, 035401, [all data]

Cavanagh, Gibson, et al., 2007
Cavanagh, S.J.; Gibson, S.T.; Gale, M.N.; Dedman, C.J.; Roberts, E.H.; Lewis, B.R.,High-resolution velocity-map-imaging photoelectron spectroscopy of the O- photodetachment fine-structure transitions,Phys. Rev. A, 2007, 76, 5, 052708, [all data]

Blondel, Chaibi, et al., 2005
Blondel, C.; Chaibi, W.; Delsart, C.; Drag, C.; Goldfarb, F.; Kroger, S.,The electron affinities of O, Si, and S revisited with the photodetachment microscope,Eur. Phys. J. D, 2005, 33, 3, 335-342, [all data]

Blondel, Delsart, et al., 2001
Blondel, C.; Delsart, C.; Goldfarb, F.,Electron spectrometry at the mu eV level and the electron affinities of Si and F,J. Phys. B: Atom. Mol. Opt. Phys., 2001, 34, 9, L281-L288, [all data]

Neumark, Lykke, et al., 1985
Neumark, D.M.; Lykke, K.R.; Andersen, T.; Lineberger, W.C.,Laser photodetachment measurement of the electron affinity of atomic oxygen,Phys. Rev. A:, 1985, 32, 1890. [all data]

Valli, Blondel, et al., 1999
Valli, C.; Blondel, C.; Delsart, C.,Measuring electron affinities with the photodetachment microscope,Phys. Rev. A, 1999, 59, 5, 3809-3815, [all data]

Lide, 1992
Lide, D.R. (Editor),Ionization potentials of atoms and atomic ionsin Handbook of Chem. and Phys., 1992, 10-211. [all data]

Kelly, 1987
Kelly, R.L.,Atomic and ionic spectrum lines of hydrogen through kryton,J. Phys. Chem. Ref. Data, 1987, 16. [all data]

Banon, Chatillon, et al., 1982
Banon, S.; Chatillon, C.; Allibert, M.,High temperature mass spectrometric study of ionization and fragmentation of TiO and TiO2 gas under electron impact,High Temp. Sci., 1982, 15, 17. [all data]

Radler and Berkowitz, 1977
Radler, K.; Berkowitz, J.,Photoionization mass spectrometric study of CSe2,J. Chem. Phys., 1977, 66, 2176. [all data]

Paule, 1976
Paule, R.C.,Mass spectrometric studies of Al2O3 vaporization processes,High Temp. Sci., 1976, 8, 257. [all data]

Hildenbrand, 1975
Hildenbrand, D.L.,Vertical ionization potential of the CF2 radical,Chem. Phys. Lett., 1975, 32, 30. [all data]

Cermak, 1975
Cermak, V.,Electron spectroscopy of autoionizing states of oxygen, chlorine and bromine atoms,J. Electron Spectrosc. Relat. Phenom., 1975, 6, 135. [all data]

Moore, 1970
Moore, C.E.,Ionization potentials and ionization limits derived from the analyses of optical spectra,Natl. Stand. Ref. Data Ser., (U.S. Natl. Bur. Stand.), 1970, 34, 1. [all data]

Jonathan, Morris, et al., 1970
Jonathan, N.; Morris, A.; Smith, D.J.; Ross, K.J.,Photoelectron spectra of ground state atomic hydrogen, nitrogen and oxygen,Chem. Phys. Lett., 1970, 7, 497. [all data]


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  • Symbols used in this document:
    EAElectron affinity
    IE (evaluated)Recommended ionization energy
    ΔrFree energy of reaction at standard conditions
    ΔrEnthalpy of reaction at standard conditions
  • Data from NIST Standard Reference Database 69:NIST Chemistry WebBook
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When the mass number of oxygen is 16, how many neutrons does oxygen have in its nucleus?

2 Answers


Mass number equals number of sub atomic particles in the nucleus.

Atomic number gives the number of protons, which equals the number of electrons. The atomic number for oxygen is 8, so the atom has 8 electrons and 8 protons.

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Protons and neutrons are found in the nucleus, so the number of neutrons is found by subtracting the proton number from the mass number I.e. 16 - 8 = 8

Oxygen exists in isotopic form and has an isotope with mass number 18. This atom will have 10 neutrons as 18 - 8 = 10


Oxygen has an atomic number of #8#, and the mass number of an atom is the sum of its atomic number plus its neutron number.

We got the mass as #16# units, and so it'll have #16-8=8# neutrons.

Atomic No Of Oxygen Used

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