Introduction to the atom along with the first 20 elements

CSEC CHEMISTRY

1. CHEMISTRYCHEMISTRY

2. IntroductionIntroduction
An atom is the smallest part of an element which can take part in a chemical
reaction.
An element is a substance that is made of only one type of atom.
A molecule is a group of two or more atoms that are chemically combined.
Molecules of an element contain only one kind of atom. Molecules of a compound
contain different kinds of atoms.
A compound is a chemical mixture of two or more elements.
A chemical symbol is a representation of an element.
 Chemical formulae indicate the number and kinds of atoms contained in a
molecule of a substance.
An ion is an atom which has acquired a charge due to a gain or loss of electrons.
An atom that loses electrons forms a positively charged ion called a cation. An atom
that gains electrons forms a negatively charged ion called an anion.
A valence refers to the number of electrons which have been gained or lost by the
atom.
A radical refers to a group of chemical substances that remains unchanged in
chemical reactions.

3. Element, Symbol and Valency
ELEMENTELEMENT SYMBOLSYMBOL VALENCYVALENCY
AluminumAluminum AlAl +3+3
BoronBoron BB +3+3
BromineBromine BrBr -1-1
BerylliumBeryllium BeBe +2+2
CarbonCarbon CC +4+4
CalciumCalcium CaCa +2+2
Copper (Cuprous)Copper (Cuprous) CuCu +1+1
Copper (Cupric)Copper (Cupric) CuCu +2+2
FluorineFluorine FF -1-1
GoldGold AuAu +1+1
HydrogenHydrogen HH +1+1
HeliumHelium HeHe 00
Iron (Ferrous)Iron (Ferrous) FeFe +2+2
Iron (Ferric)Iron (Ferric) FeFe +3+3
IodineIodine II -1-1

4. ELEMENTELEMENT SYMBOLSYMBOL VALENCYVALENCY
Lead (Plumbous)Lead (Plumbous) PbPb +2+2
Lead (Plumbic)Lead (Plumbic) PbPb +4+4
MagnesiumMagnesium MgMg +2+2
ManganeseManganese MnMn +2+2
Mercury (Mercurous)Mercury (Mercurous) HgHg +1+1
Mercury (Mercuric)Mercury (Mercuric) HgHg +2+2
NitrogenNitrogen NN -3-3
NeonNeon NeNe 00
OxygenOxygen OO -2-2
PotassiumPotassium KK +1+1
PhosphorusPhosphorus PP -3-3
SilverSilver AgAg +1+1
SiliconSilicon SiSi +2+2
SodiumSodium NaNa +1+1
ChlorineChlorine ClCl -1-1
LithiumLithium LiLi +1+1

5. Radical, Symbol and ValencyRadical, Symbol and Valency
RadicalRadical SymbolSymbol ValencyValency
SulphateSulphate (SO(SO44)) -2-2
SulphiteSulphite (SO(SO33)) -2-2
NitrateNitrate (NO(NO33)) -1-1
NitriteNitrite (NO(NO22)) -1-1
CarbonateCarbonate (CO(CO33)) -2-2
Hydrogen Hydrogen
CarbonateCarbonate
(HCO(HCO33)) -1-1
PhosphatePhosphate (PO(PO44)) -3-3
PhosphitePhosphite (PO(PO33)) -3-3
HydroxideHydroxide (OH)(OH) -1-1
AmmoniumAmmonium (NH(NH44)) +1+1

6. Reference WebsitesReference Websites
http://en.wikipedia.org/wiki/Radical_(chemistry)
http://chemistry.about.com/od/elementfacts/a/elementsymbols.htm
http://en.wikipedia.org/wiki/Valence_(chemistry)