1.1Atomic structure

• The order of subatomic particles how they were discovered

  Electrons

  Protons

  Neutrons
• The nucleus is 10,000 time smaller than size of atom
• Atoms have same number of protons and electrons so overall charge is 0
• Before discovery of electrons it was thought atoms couldn't be divided any further
• Most of atoms is empty space with most of the mass is concentrated in the centre
• The nucleus is positively charged

  The electrons are negative
• Proton has relative charge of?

  Neutron has relative charge of?

  Electron has relative charge of?

  +1

  0

  -1
• Relative mass:

  • Proton is 1
  • Neutron is 1
  • Electron is 0
• Atoms of same element have same atomic number

  Atoms of different elements have different atomic number
• Element have relative atomic masses that aren't whole numbers because of how common or rare an elements isotope is
• Isotopes are atoms of the same element with same number of protons but they have different numbers of neutrons
• Calculating atomic mass

  Sum of (% abundance x mass no.)/ Sum of abundances of all the isotopes
• Atom has typical radius of 0.1nm (1 × 10^-10)

  Water molecule has diameter of 0.3nm (2 × 10^-10)
• What is mass number

  Totally nu,ber of protons and neutrons