C1 particles

• Solid

  Regular arrangement

  very close together

  vibrate around fixed points

  
• liquid

  random arrangement

  close together

  move around each other

  
• gas

  random arrangement

  far apart

  move rapidly in random direction

  
• limitations of the particle model

  Doesn’t show forces between particles

  doesnt show size of particles

  doesnt show space between particles
• characteristics of a physical change

  no new substances are made

  when a substance changes state/ shape

  if it breaks into new pieces

  (usually) reversible
• characteristics of a chemical change

  new substances are made with different properties to original substance

  difficult/ impossible to reverse
• subatomic structures of the atom

  proton

  neutron

  electron
• properties of proton

  relative mass = 1

  charge +1
• properties of neutron

  relative mass = 1

  charge =0
• properties of electrons

  relative mass = negligible

  charge =-1
• isotope definition

  atoms of the same element with the same number of protons but different number of neutrons.
• ions

  charged particles

  formed when an atom loses or gains electrons to become stable

  eg. sodium= Na+, oxygen= O^2-
• developing the atomic model (dalton)

  all atoms of an element are identical

  different elements contain different types of atom
• developing atomic model (Thomson)

  atoms contain electrons

  atoms are neutral overall

  plum pudding model= dense positive sphere with negatively charged electrons embedded within
• developing atomic model (rutherford)

  alpha particle fired at thin gold foil

  positive nucleus containing most of mass (some reflected)

  electrons orbit around outside
• developing atomic model (Bohr)

  electrons occupy fixed energy levels/shells around nucleus

  attracted to oppositely charged nucleus
• Solid - liquid

  melting
• liquid -gas

  evaporation
• gas- liquid

  condensing
• gas -solid

  deposition
• solid- gas

  sublimation
• liquid-solid

  freezing