• Atomic Number 83
• Atomic Number 89
• Atomic Number 81

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• The atomic number of an atom is defined by the number of protons. Thus, if the given atom has an atomic number of 8, it means that it has 8 protons. When the atom is neutrally charged, there is an.
• 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.
• Relative atomic mass The mass of an atom relative to that of carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists, the value given is the abundance weighted average. Isotopes Atoms of the same element with different numbers of neutrons.

Atomic Number: 8 Atomic Mass: 15.9994 amu Melting Point:-218.4 °C (54.750008 K, -361.12 °F) Boiling Point:-183.0 °C (90.15 K, -297.4 °F) Number of Protons/Electrons: 8 Number of Neutrons: 8 Classification: Non-metal Crystal Structure: Cubic Density @ 293 K: 1.429 g/cm 3 Color: colorless Atomic Structure. Atomic Number of Oxygen. 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. Atomic Mass of Oxygen. Atomic mass of Oxygen is 15.9994 u. Note that, each element may contain more isotopes, therefore this resulting atomic mass is calculated from naturally-occuring isotopes and their abundance.

Notes:
• Density of elements with boiling points below 0°C is given in g/l. In a sorted list, these elements are shown before other elements that have boiling points >0°C.
• Earth crust composition average values are from a report by F. W. Clarke and H. S. Washington, 1924. Elemental composition of crustal rocks differ between different localities (see article).
• Group: There are only 18 groups in the periodic table that constitute the columns of the table. Lanthanoids and Actinoids are numbered as 101 and 102 to separate them in sorting by group.
• The elements marked with an asterisk (in the 2nd column) have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Abbreviations and Definitions:

No. - Atomic Number; M.P. - melting point; B.P. - boiling point

Atomic number: The number of protons in an atom. Each element is uniquely defined by its atomic number.

Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Atomic mass is measured in Atomic Mass Units (amu) which are scaled relative to carbon, ¹²C, that is taken as a standard element with an atomic mass of 12. This isotope of carbon has 6 protons and 6 neutrons. Thus, each proton and neutron has a mass of about 1 amu.

Atomic Number 83

Isotope: Atoms of the same element with the same atomic number, but different number of neutrons. Isotope of an element is defined by the sum of the number of protons and neutrons in its nucleus. Elements have more than one isotope with varying numbers of neutrons. For example, there are two common isotopes of carbon, ¹²C and ¹³C which have 6 and 7 neutrons respectively. The abundances of different isotopes of elements vary in nature depending on the source of materials. For relative abundances of isotopes in nature see reference on Atomic Weights and Isotopic Compositions.

Atomic weight: Atomic weight values represent weighted average of the masses of all naturally occurring isotopes of an element. The values shown here are based on the IUPAC Commission determinations (Pure Appl. Chem. 73:667-683, 2001). The elements marked with an asterisk have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Electron configuration: See next page for explanation of electron configuration of atoms.

Atomic Number 89

Ionization energy (IE): The energy required to remove the outermost electron from an atom or a positive ion in its ground level. The table lists only the first IE in eV units. To convert to kJ/mol multiply by 96.4869. Reference: NIST Reference Table on Ground states and ionization energies for the neutral atoms. IE decreases going down a column of the periodic table, and increases from left to right in a row. Thus, alkali metals have the lowest IE in a period and Rare gases have the highest.

Other resources related to the Periodic Table

Atomic Number 81

• Chemical Evolution of the Universe