CHEMICAL SYMBOLS AND FORMULAE
An element is a substance which consists of only one kind of matter Over 100 elements are known, these elements are usually represented by symbols instead of writing their names in full.
The abbreviation for each element is called Symbol for that element.
The brief name of that element it represents also one atom of the element it stands for. (Element1–20)
There are 4 groups of symbols:
Symbols formed from the first letter of element
(b) Symbols formed from the first two letter of the element.
(c) Symbols formed from the first and any letter in the name of the elements
(d) Symbols derived from latin name of the elements
Element Latin Name Symbols
Sodium Natrium Na
Iron Ferrum Fe
Copper Cuprum Cu
Gold Aurum Au
Potassium Kalium K
Silver Argentun Ag
Lead Plumbum Pb
Mercury Hydragyrum Hg
Electronic Configuration is the representation of how electrons are arranged on the shells of an element.
The pattern of how electrons are arranged is of the fashion:
This pattern works for at least the first 20elements.
The electronic configuration helps us to correctly place elements into their groups and period within periodic table. This information also helps in the determination of combining powers of elements.
GROUP AND VALENCY
The group refers to the vertical arrangement in columns of elements in the periodic table. Valency is the combining power of an element. It must be correctly determined and the correct chemical formulae of compound were to be determined.
FORMULAE OF BINARY COMPOUND
Formulae of binary compound
A compound is a substance made of 2 or more elements chemically combined together. Compound of 2 elements only are known as binary compounds and have the following characteristics.
- Name send with–IDE.
E.g. Carbon dioxide, Magnesium chloride, Aluminum Oxide, Aluminum Chloride.
Mg=12______2, 8, 2O=8______2, 6
Cl=17 _______2, 8, 7
Mg Cl A1 0
+2 1 +3 2
These are compounds of 2 or more elements whose name send with ATE examples are: Magnesium trioxocarbonate (IV)
Beryllium trioxonitrate (V)
Calcium tetraoxosulphate (VI)
Potassium heptaxodichromate VI
Sodium hexachloroplatimate II
Non-binary compounds have these characteristics:
- Trioxonitrate (V) ion N03–
- Trioxocarbonate(IV) ion C032-
- Tetraoxosulphate(VI) ion S042–
- Hydroxideion OH–
- Cyanideion CH–
- Tetraoxophosphate (V) ion PO43-
- Hydrogentrioxocarbonate(IV)ion HC03–
The charge one achpoly atomic ionis determined thus:
FORMULAE OF NON-BINARY COMPUNDS
Sodium hexachloroplatinate II
Na=11________2, 8, 1
Valency of sodium =1
Hexachlroroplatinate II = PtCl6
International Union of Pure and Applied Chemistry have agreed to a common way of naming chemical compounds according to a set of rules, these naming system is termed IUPAC nomenclature.
The rules involved in IUPAC nomenclature are as follow:
Take oxygen as–2.
Hydrogen as +1 with non-metals.
Hydrogen as–1 with metals.
These numbers are the oxidation number.
Name = trioxocarbonate (IV) ioni.e.3atoms of oxygen and carbon oxidation number is 4.