The atomic number uniquely identifies a chemical element.

Each element has a specific set of chemical properties as a consequence of the number of electrons present in the neutral atom, which is Z ( the atomic number ).

Hence it is the atomic number alone that determines the chemical properties of an element ; and it is for this reason that an element can be defined as consisting of any mixture of atoms with a given atomic number.

Argon ( ) is a chemical element with symbol Ar and atomic number 18.

The name " argon " is derived from the Greek word αργον meaning " lazy " or " the inactive one ", a reference to the fact that the element undergoes almost no chemical reactions.

Arsenic ( ) is a chemical element with symbol As and atomic number 33.

Antimony ( or ; ) is a toxic chemical element with symbol Sb and atomic number 51.

Actinium ( ) is a radioactive chemical element with symbol Ac and atomic number 89, which was discovered in 1899.

Americium ( ) is a transuranic radioactive chemical element that has the symbol Am and atomic number 95.

Astatine ( or ) is a radioactive chemical element with the chemical symbol At and atomic number 85.

An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element.

The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties.

He proposed that each element consists of atoms of a single, unique type, and that these atoms can join together to form chemical compounds.

* Americium, a chemical element

* Of or relating to the Atom, the smallest particle of a chemical element that retains its chemical properties

of atoms, in the modern sense of the basic unit of a chemical element.

* 1982 – The synthetic chemical element Meitnerium, atomic number 109, is first synthesized at the Gesellschaft für Schwerionenforschung in Darmstadt, Germany.

This text clarified the concept of an element as a substance that could not be broken down by any known method of chemical analysis, and presented Lavoisier's theory of the formation of chemical compounds from elements.

Allotropes are different structural forms of the same element and can exhibit quite different physical properties and chemical behaviours.

* Gold, a chemical element with the symbol Au

The drug's chemical name is listed, since most states require feed processors to use this name instead of the trade name on the feed tag.

In some instances, the trade name is shown in parentheses following the chemical name.

Even here there is room for some variation, for metal surfaces vary in smoothness, absorptive capacity, and chemical reactivity.

As is well known, detergent actives belong to the chemical class consisting of moderately high molecular weight and highly polar molecules which exhibit the property of forming micelles in solution.

On chemical grounds it seems most likely that iodide is first converted to Af and then to Af as the active iodinating species.

The chemical nature of the iodocompounds is discussed below ( pp. 76 et seq. ).

It is therefore necessary to consider the properties of pituitary TSH if the fragmentary chemical information about blood TSH is to be discussed rationally.

The importance of knowing in what chemical forms the hormone may exist is accentuated by the recent observation that there exists an abnormally long-acting TSH in blood drawn from many thyrotoxic patients ( Adams, 1958 ).

Whether this abnormal TSH differs chemically from pituitary TSH, or is, alternatively, normal TSH with its period of effectiveness modified by some other blood constituent, cannot be decided without chemical study of the activity in the blood of these patients and a comparison of the substance responsible for the blood activity with pituitary Aj.

The aim is to collect a very broad range of physical, chemical, morphological, and structural data for crystals on an encyclopedic scale and to seek all possible useful and revealing correlations of properties with internal structure.

The process in which the outcome of any one stage is known only statistically is also of interest, although for chemical reactor design it is not as important as the deterministic process.

It is a popular belief that alchemists made contributions to the " chemical " industries of the day — ore testing and refining, metalworking, production of gunpowder, ink, dyes, paints, cosmetics, leather tanning, ceramics, glass manufacture, preparation of extracts, liquors, and so on ( it seems that the preparation of aqua vitae, the " water of life ", was a fairly popular " experiment " among European alchemists ).

Experiments have been conducted to attempt the synthesis of ununennium ( Uue ), which is likely to be the next member of the group, but they have all met with failure .< ref name =" link "> However, ununennium may not be an alkali metal due to relativistic effects, which are predicted to have a large influence on the chemical properties of superheavy elements.

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.

Originally, the term antioxidant specifically referred to a chemical that prevented the consumption of oxygen.

Applied quantum chemistry, specifically, orbital hybridization best describes chemical bonding in nanotubes.

Walter Heitler and Fritz London are credited with the first successful quantum mechanical explanation of a chemical bond, specifically that of molecular hydrogen, in 1927.

A chemical linker synthesized with an alpha-1, 3-gal-gal bond on one end and a DNA aptamer devised to bind specifically to the strain of influenza you have on the other end will link anti-alpha-Gal antibodies to the influenza virus and presto !-- you have fooled your immune system into attacking the new virus.

Smalley's latest research was focused on carbon nanotubes, specifically focusing on the chemical synthesis side of nanotube research.

There are a number of electron microscopes that have been specifically designed for use in Auger spectroscopy ; these are termed scanning Auger microscopes ( SAM ) and can produce high resolution, spatially resolved chemical images.

* Listed hazardous waste are materials specifically listed by regulatory authorities as a hazardous waste which are from non-specific sources, specific sources, or discarded chemical products.

Many modern chemical herbicides for agriculture are specifically formulated to decompose within a short period after application.

However, diazinon use has been discouraged by EPA in favor of chemical preservatives, which alter the taste of the roots and more specifically target grubs without affecting other insect species as does diazinon or other poisons.

This is because the term semimetal has a different meaning in physics, one which more specifically refers to the electronic band structure of a substance rather than the overall classification of a chemical element.

It specifically affects plant nutrient availability by controlling the chemical forms of the nutrient.

But nicotine later came to refer specifically to the particular chemical in the plant.

As defined by IUPAC, rare earth elements (" REEs ") or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium.

No resolution was passed during the war that specifically criticized Iraq's use of chemical weapons, despite the wishes of the majority to condemn this use.

Dry chemicals have since fallen out of favor for kitchen fires, as they have no cooling effect compared to the extremely effective wet chemical agents specifically designed for such hazards.

" Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a " substance that is consumed in the course of a chemical reaction ".

* Forensic taphonomy specifically studies the processes of decomposition in order to apply the biological and chemical principles to forensic cases in order to determine post-mortem interval ( PMI ), post-burial interval as well as to locate clandestine graves.

A. percula is associated specifically with Heteractis magnifica and Stichodactyla gigantea, and as larva use chemical cues released from the anemones to identify and locate the appropriate host species to use them for shelter and protection.

The abstract definition of chemical potential given above — total change in free energy per extra mole of substance — is more specifically called total chemical potential.

That is to say, anhydrous matter is prepared or used as a form with no water, and specifically the form of a chemical without water of crystallization.

Lastly, using DES as an " environmental estrogen ", a 2009 animal study determined prenatal exposure disrupts specialized brain cells and their ability to regulate brain chemistry, specifically altering the way cells release and reabsorb dopamine, an important chemical messenger that governs movement and pleasure.

Experimental design remains a core area of study in chemometrics and several monographs are specifically devoted to experimental design in chemical applications.

The text presents a vignette from the front lines of World War I ; specifically, of British soldiers attacked with chemical weapons.