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Carbon 6 C 12.011: Nitrogen 7 N 14.007: Oxygen 8 O 15.999: Fluorine 9 F 18.998: Neon 10 Ne 20.180: 3: Sodium 11 Na 22.990: Magnesium 12 Mg 24.305: Aluminium 13 Al 26.982: Silicon 14 Si 28.085: Phosphorus 15 P 30.974: Sulfur 16 S 32.06: Chlorine 17 Cl 35.45: Argon 18 Ar 39.95: 4: Potassium 19 K 39.098: Calcium 20 Ca 40.078 ...
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Small symbols pack in additional information: solid/liquid/gas, the color of an element, common in the human body, common in the earth's crust, magnetic metals, noble metals, radioactive, and rare or never found in nature. It does not overload kids with a lot of detailed numbers, like atomic weights and valence numbers.
Substantial deviations in atomic weight of the element from that given in the table can occur. r Range in isotopic composition of normal terrestrial material prevents a more precise standard atomic weight being given; the tabulated value and uncertainty should be applicable to normal material.
Hydrogen is the element with atomic number 1; helium, atomic number 2; lithium, atomic number 3; and so on. Each of these names can be further abbreviated by a one- or two-letter chemical symbol; those for hydrogen, helium, and lithium are respectively H, He, and Li. [6] Neutrons do not affect the atom's chemical identity, but do affect its weight.
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
The mass number (symbol A, from the German word: Atomgewicht, "atomic weight"), [1] also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approximately equal to the atomic (also known as isotopic) mass of the atom expressed in atomic mass units.
Various letters, such as "m" and "f" may also be used here to indicate a nuclear isomer (e.g., 99m Tc). Alternately, the number here can represent a specific spin state (e.g., 1 O 2). These details can be omitted if not relevant in a certain context. The proton number (atomic number) may be indicated in the left subscript position (e.g., 64 Gd ...