atomic number

In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, the atomic number is also equal to the number of electrons.

The atomic number, Z, should not be confused with the mass number, A, which is the total number of protons and neutrons in the nucleus of an atom. The number of neutrons, N, is known as the neutron number of the atom; thus, A = Z + N. Since protons and neutrons have approximately the same mass (and the mass of the electron is negligible for many purposes), the atomic mass of an atom is roughly equal to A.

Atoms having the same atomic number Z but different neutron number N, and hence different atomic mass, are known as isotopes. Most naturally occurring elements exist as a mixture of isotopes, and the average atomic mass of this mixture determines the element's atomic weight. Wikipedia

[1] See "The Ox and the Chamois" in Nature as Teacher, p.41, Vol. II of the Ecotechnology series. — Ed.
[2] H-substance: here refers to hydrogen or hydrogen-like substances. — Ed.
[3] Phos-elements: It is not quite clear what is intended here, but it may relate in some way to bioluminescence. However, the following three definitions are provided as an aid to interpretation.
PHOSPHOR: A substance which is capable of luminescence, i.e. storing energy (particularly from ionising radiation) and later releasing it in the form of light. If the energy is released after only a short delay (between 10-10 and 10-4 seconds) the substance is called a 'scintillator'.
PHOSPHORUS: P. Element. Atomic weight 30.9738. Atomic number 15. Occurs in several allotropic forms, white phosphorus and red phosphorus being the commonest. The former is a waxy white, very inflammable and poisonous solid. Red phosphorus is a non-poisonous, dark red powder, not very inflammable. The element only occurs in the combined state, mainly as calcium phosphate, CA3(PO4)2, Essential to life; calcium phosphate is the main constituent of animal bones.
PHOSPHATE: Salt of phosphoric acid H3PO4. Phosphates are used as fertilisers to rectify a deficiency of phosphorus in the soil. Note: The editor regrets that he cannot locate the dictionary from which the information was originally sourced.' [The Energy Evolution - Harnessing Free Energy from Nature, Letter to Werner Zimmermann]

See Also

atomic mass
atomic weight

Created by admin. Last Modification: Monday September 19, 2022 04:48:56 MDT by Dale Pond.