Chemistry - Atomic Structure

Chemistry - Atomic Structure

1. Atoms

   • Protons + neutrons = atomic mass
   • Protons = atomic number
   • Proton: relative mass = 1 charge = +1
   • Neutron: relative mass = 1 charge= 0
   • Protons = electrons
   • Electron: relative mass = 1/1836 charge = -1
   • Isotopes are atoms of the same element, they contain the same number of protons and electrons but different number of neutrons

2. Changes of State

   • Solid
     • Strong forces of attraction
     • Regular lattice arrangement
     • Particles vibrate, more so the heated
   • Liquid
     • Weak forces of attraction
     • Definite volume but no fixed shape
     • Particles move randomly
   • Gas
     • Very weak forces of attraction
     • Free to move around
     • No definite shape or volume

3. Diffusion

   • The gradual movement of particles from areas of high concentration to areas of low concentration
   • It is quicker in gases
   • Slower in a liquid because the particles in a liquid move slower