Most naturally occurring elements exist as a mixture of isotopes, and the average atomic mass of this mixture determines the element's atomic weight.

The relative atomic mass ( historically and commonly also called " atomic weight ") of an element is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance, relative to the atomic mass unit ( u ).

Isotopes are distinguished by the atomic mass number ( total protons and neutrons ) for a particular isotope of an element, with this number combined with the pertinent element's symbol.

Given is each element's name, atomic number, year of first report, name of the discoverer, and some notes related to the discovery.

The chemical abbreviation for sodium was first published by Jöns Jakob Berzelius in his system of atomic symbols, and is a contraction of the element's new Latin name natrium, which refers to the Egyptian natron, a natural mineral salt primarily made of hydrated sodium carbonate.

The modern periodic law states that an element's chemical and physical properties is a periodic function of its atomic number.

The fact that only certain colors appear in an element's atomic emission spectrum means that only certain frequencies of light are emitted.

In 1914 Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number ( Z ), and therefore resequenced the table by nuclear charge rather than atomic weight.

Before this discovery, atomic numbers were just sequential numbers based on an element's atomic weight.

This element's nucleus then also emits an electron and becomes a new element of mass 239 but with an atomic number 94 and a much greater half-life.

* AZE notation for isotopes: where A is the mass number, Z the atomic number, and E the element's chemical symbol.

Until Moseley's work, " atomic number " was merely an element's place in the periodic table, and was not known to be associated with any measureable physical quantity.

Moseley was able to show that the frequencies of certain characteristic X-rays emitted from chemical elements are proportional to the square of a number which was close to the element's atomic number ; a finding which supported van den Broek and Bohr's model of the atom in which the atomic number is the same as the number of positive charges in the nucleus of the atom.

In particular, only two years before Rutherford in 1911 had postulated that Z for gold atoms might be about half of its atomic weight, and only shortly afterward, Antonius van den Broek had made the bold suggestion that Z was not half of the atomic weight for elements, but instead was exactly equal to the element's atomic number, or place in the periodic table.

Using x-ray diffraction techniques in 1913-1914, Moseley found that the most intense short-wavelength line in the x-ray spectrum of a particular element was indeed related to the element's periodic table atomic number, Z.

Each atom is modeled by a sphere with the element's Van der Waals radius.

The number of electrons in each element's electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior.

Otherwise, if the sought key is less than the middle element's key, then the algorithm repeats its action on the sub-array to the left of the middle element or, if the input key is greater, on the sub-array to the right.

For purposes of international communication and trade, the official names of the chemical elements both ancient and more recently recognized are decided by the International Union of Pure and Applied Chemistry ( IUPAC ), which has decided on a sort of international English language, drawing on traditional English names even when an element's chemical symbol is based on a Latin or other traditional word, for example adopting " gold " rather than " aurum " as the name for the 79th element ( Au ).

The opposite of electronegativity is electropositivity: a measure of an element's ability to donate electrons.

The element's major use ( more that 80 % of world rhodium production ) is as one of the catalysts in the three-way catalytic converters in automobiles.

Since this element's thermal expansion is similar to borosilicate glass, it is used for making glass-to-metal seals.

The effects of an element's behaviour are fed back to in such a way that the element itself is altered.

If there is disparity between the jumps of each partner, the element's base value and grade of the jump will be scored on the partner that was less successful, even if the other partner's jump was clean.

Instead, a generic method is built into the element's abstract class.

A more detailed study by the Brazilian Center for Physics Research ( CBPF ) on the element's isotopes shows similar results ( in particular that < sup > 296 </ sup > Uus is the most stable isotope in its region ), but goes further up to < sup > 337 </ sup > Uus.

The modern chemical symbol for sodium, Na, is an abbreviation of that element's New Latin name natrium, which was derived from natron which refers to Wadi El Natrun or natron valley in Egypt from which natron was mined in ancient Egypt for use in burial rites.

In electrical and electronic systems, reactance is the opposition of a circuit element to a change of electric current or voltage, due to that element's inductance or capacitance.

The Q is a measure of the ratio of reactance to resistance, so with a fixed radiation resistance ( an element's radiation resistance is almost independent of its diameter ) a greater reactance off-resonance corresponds to the poorer bandwidth of a very thin conductor.

* Cam operation, which is related in principle to tracing but can be a step or two removed from the traced element's matching the reproduced element's final shape.

For example, the stability and low energy of the electron cloud state in helium accounts for the element's chemical inertness, and also the lack of interaction of helium atoms with each other, producing the lowest melting and boiling points of all the elements.

For example, the stability and low energy of the electron cloud state in helium accounts for the element's chemical inertness ( the most extreme of all the elements ), and also the lack of interaction of helium atoms with each other ( producing the lowest melting and boiling points of all the elements ).

His results showed unequivocally that Meyer's interpretation was the correct one and that nearly all of the new element's properties matched Mendeleev predictions.

The " lossy " dielectric complex reluctance represents a dielectric circuit element's resistance to not only electric induction flux but also to changes in electric induction flux.

The " lossy " magnetic complex reluctance represents a magnetic circuit element's resistance to not only magnetic flux but also to changes in magnetic flux.

The effect of cooling was to expand the seeker's lead sulphide detector element's sensitivity range to longer wavelengths ( slightly over 4 µm as opposed to 2. 8 µm of uncooled PbS elements ).

Nickel-78 is the element's heaviest isotope and is believed to have an important involvement in supernova nucleosynthesis of elements heavier than iron.

Fibonacci heaps can insert elements, query the highest priority element, and increase an element's priority in amortized constant time though deletions are still O ( log n )).

The behaviour of individual elements is characterised by the element's stiffness or flexibility relation, which altogether leads to the system's stiffness or flexibility relation.

To establish the element's stiffness or flexibility relation, we can use the mechanics of materials approach for simple one-dimensional bar elements, and the elasticity approach for more complex two-and three-dimensional elements.

When the prime is 2, it is conventional to express elements of GF ( p < sup > n </ sup >) as binary numbers, with each term in a polynomial represented by one bit in the corresponding element's binary expression.

A flame test is a procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic emission spectrum.