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A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs.
For example, for the compound FeCl 3, the cation, iron, can occur as Fe 2+ and Fe 3+. In order for the compound to have a net charge of zero, the cation must be Fe 3+ so that the three Cl − anions can be balanced (3+ and 3− balance to 0). Thus, this compound is termed iron(III) chloride. Another example could be the compound PbS 2.
Note that "group" has a chemical meaning and "column" has the tabular meaning. Alternatively, they may be named by their first element, e.g. "boron group" for group 13. [2] (But per below, avoid iron group for group 8 as ambiguous.) In the 1–18 scheme, f-block groups are unnumbered.
A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8, meaning each oxygen atom has 8 protons in its nucleus.
This is a list of common chemical compounds with chemical formulae and CAS numbers, indexed by formula. This complements alternative listing at list of inorganic compounds . There is no complete list of chemical compounds since by nature the list would be infinite.
Single atom anions are named with an -ide suffix: for example, H − is hydride. Compounds with a positive ion : The name of the compound is simply the cation's name (usually the same as the element's), followed by the anion. For example, NaCl is sodium chloride, and CaF 2 is calcium fluoride.
A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using chemical symbols for the chemical elements, and subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is H 2 O.
Chemical formulas can be used to describe the relative amounts of elements present in a compound. For example, the chemical formula for water is H 2 O: this means that each molecule of water is constituted by 2 atoms of hydrogen (H) and 1 atom of oxygen (O). The chemical composition of water may be interpreted as a 2:1 ratio of hydrogen atoms ...