Atoms

• Define element

  Substance containing only one type of atom
• Define compound

  Substance with 2 or more different types of atoms chemically bonded
• What was John Daltons theory

  Matter is made of invisible particles
• What did JJ Thomson discover

  Atoms were made of positive and negative charges

  • Plum pudding model
• What did Ernest Rutherford discover

  The nucleus was small and positively charged
• What did Neils Bohr discover

  That electrons exist in shells
• What did James Chadwick Discover

  Nucleus must contain neutrons and protons
• Relative Charge of proton

  +1
• Relative charge of neutron

  0
• Relative charge of electron

  -1
• Relative mass of proton

  1
• Relative mass of neutron

  1
• Relative mass of electron

  Negligible
• What is the atomic number

  Number of protons in a nucleus

  • Bottom number
• What is the mass number

  Number of protons + neutrons in a nucleus

  • Top number
• Define isotope

  Element with the same number of protons but different number of neutrons
• What is the atomic number the same as

  Number of electrons