Definition of Element : Pure substances that cannot be split up into two or more simpler substances by chemical processed or by electricity.
Examples : Sugar, Water ≠ Element (because they can be broken down to water + carbon and hydrogen + oxygen respectively) However, the last 4 ARE elements because they cannot be furthar broken down.
- Chemicals use chemical symbols to represent elements.
- Elements -> 2 Groups -> Metals/Non-Metals
- Some elements have properties of both metal and non-metals, though.
- The atom is the smallest particle of an element that has the chemical properties of an element.
- Not all elements exist as atoms.
- Metals exist as atoms in a giant structure. Most non-metals exist as molecules.
- A molecule is made up of 2 or MORE atoms that are chemically combined.
- Molecules that are formed by 2 atoms -> Diatomic Molecules
- Molecules that are formed by 4 or more atoms -> Polyatomic Molecule
Referance : G.C.E 'O' Level Chemistry Matters Textbook Pages 59-63
A chemical element is a substance that cannot be broken down by chemical means. Elements are defined by the number of protons they possess.
Proton = A proton is a component of an atomic nucleus with a mass defined as 1 and a charge of +1. The nucleus of a hydrogen atom. The H+ ion.
Valence = Valence is typically, the number of electrons needed to fill the outermost shell of an atom.
Electron = negatively charged component of an atom. Electrons exist outside of and surrounding the atom nucleus. Each electron carries one unit of negative charge and has a very small mass as compared with that of a neutron or proton.
Neutron = The neutron is the particle in the atomic nucleus with a mass = 1 and charge = 0.
Atom = An atom is the defining structure of an element, which cannot be broken by any chemical means. A typical atom consists of a nucleus of protons and neutrons with electrons orbiting this nucleus.
Molecule = a molecule refers to two or more atoms which have chemically combined to form a single species.
Referances :
http://chemistry.about.com/od/chemistryglossary/a/elementdef.htm
http://chemistry.about.com/od/chemistryglossary/a/protondef.htm
http://chemistry.about.com/od/chemistryglossary/g/moleculedef.htm
http://chemistry.about.com/od/chemistryglossary/a/neutrondef.htm
http://chemistry.about.com/od/chemistryglossary/a/atomdefinition.htm
http://chemistry.about.com/od/chemistryglossary/a/electrondef.htm
http://chemistry.about.com/od/chemistryglossary/a/valencedef.htm
