Sub Atomic Particles

Property          Proton     Neutron    Electron

Mass /kg           1.673x10^-27   1.675x10^-27   0.911x10^-30
Relative Mass         1               1               0

Charge /C       +1.602x10^-19         0        -1.602x10^-19

Relative Charge     +1              0              -1

Position             Nucleus     Nucleus       Orbital

The Arrangement of Sub-atomic Particles

The protons and Neutrons are held together in the center of the atom by the STRONG NUCELAR FORCE.

The Electrons and Protons are held together by ELECTROSTATIC FORCES.

Electrons are found in a series of levels which get further and further away from the nucleus.

Electron Shields

The shell closest to the nucleus fills first. 

The Shell furthest from the nucleus empties first.

First Shell = 2 Electrons

Second Shell = 8 Electron

Third Shell = 18 Electrons

Electron Diagrams

Atomic Number, Z

Atomic Number = Proton Number

Number of Electrons = Number of Protons

so....

Atomic Number = Electron Number

Mass Number, A

Mass Number = Protons + Neutrons

Mass Number = Nucleon Number

Isotopes

Isotopes have the same number of Protons and Electrons but have a different number of Neutrons.

They are Chemically the same but have a different mass

Energy Levels

Electrons in different shells have different energys.

Levels can hold 2n² electrons.

Energy levels divided into sub-levels.

Atomic Orbitals

Electron = Cloud of Negative Charge.

S-Orbitals = 2 Electrons

P-Orbitals = 3x 2 Electrons

D-Orbitals = 5x 2 Electrons

Sub-Level Arrangement

Main Energy Level   1       2        3            4 

Sub Levels             s      s,p     s,p,d     s,p,d,f

Orbitals                 1     1,3     1,3,5     1,3,5,7

Electrons               2     2,6    2,6,10   2,6,10,14 Total Electrons       2      8        18           32  

Putting Electrons into Atomic Orbitals

Lower Energy Levels are filled First.

All levels one one Energy filled before Paring.

No atomic orbitals can hold more than 2 Electrons.

Writing Electronic Structures

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

Ionisation Energy

Ionisation energy is the energy required to remove one mole of electrons from an element in a gaseous state.

Ionisation Energy = IE

Na_(g) → Na⁺_(g) + e^-

Trends in ionisation energies across a period

Generally Increase - Nucleur Charge increases, but same Electron Shielding

Increase in  zig zag pattern - Sub-Orbitals

Slight Dip when Electrons Start to Pair up.

Trend in Ionisation energies down a Group.

General Decrease - Outer electron is further from the Nucleus.

Inner Electron Levels make Electron Shielding