Chem C3 - Arrangement of electrons in the atom

Ernest Rutherford

proposed electrons revolve around the nucleus like the planets around the sun - defied the laws of physics

Niels Bohr

proposed electrons revolve around the nucleus in fixed paths or orbits called energy levels.

emission line spectrum

the light from a hydrogen discharge tube is passed through a prism producing a series of narrow coloured lines.

energy level

defined as the fixed energy value that an electron in an atom may have

Lyman series

found in the ultraviolet region when electrons fall back to n=1

Balmer series

visible in the spectrum, arise when excited electrons fall back to n=2

Paschen series

found in the infared region when electrons fall back to n=3

Copper sulphate flame

blue-green

lithium carbonate flame

deep red

sodium sulphate flame

yellow

strontium nitrate flame

red

barium nitrate flame

yellow-green

potassium sulfate flame

lilac

Louid de Broglie

proposed all moving particles have a wave motion

Heisenbergs uncertainty principle

you cannot measure at the same time both the speed of an electron and its distance from the nucleus

Orbital

an atomic orbital is a region in space around the nucleus within which there is a high probability of finding an electron

Aufbau Principle

electrons occupy the lowest energy level available

Hands rule of maximum multiplicity

when there are two or more orbitals of the same energy electrons occupy them singly before filling them in pairs

Pauli exclusion principle

no more than two electrons can occupy an orbital and they must have opposite spin

absorption spectrum

the absorption spectrum of an element is the spectrum that is observed after light has been passed through the element