Thursday, 9 February 2012

Atomic Structure...simplified

Atom                smallest part of an element. Cannot be broken down into anything simpler in a chemical reaction.
Molecule          two or more atoms covalently bonded together.
Ion                    a charged particle. Usually formed when atoms lose or gain electrons.
Compound      substance containing two or more elements bonded together.
Proton             a particle found in the nucleus. It has a mass of 1 and a charge of +1.           
Neutron           a particle found in the nucleus. It has a mass of 1 and a charge of 0.
Electron          found in shells around the nucleus. It has a mass of 1/2000 and a charge of -1.

The nucleus is tiny compared to the size of the atom but it contains nearly all of the mass of the atom.
In an atom the number of protons is equal to the number of electrons, therefore, the charges cancel each other out so the atom has no charge.
If an atom has gained an electron(s) it becomes a negative ion and so has more electrons than protons.
If an atom has lost an electron(s) it becomes a positive ion and so has more protons than electrons.
  • ‘12’ is representing the atomic number, which tells us the number of protons.
  • ‘6’ is the mass number that equals the number of protons + the number of neutrons.
  • So the number of neutrons  =  mass number  -  atomic number

Isotopes            atoms of the same element with the same number of protons (atomic number) but different number of neutrons (mass number).
They have the same number of electrons in their outer shell and therefore do the same chemical reactions.
They can be detected by using a mass spectrometer, which I will talk about in one of my later blogs. 

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