atomic structure and periodic table

• what was the first sub atomic particle to be discovered 


  electron
• what atomic model was suggested after the discovery of electrons 


  plum pudding model
• in the plum pudding model the atom is a ball of positive charge
• the plum pudding model has negative electrons embedded in it
• why was gold used in the alpha scattering experiment 


  it can be hammered into very thin foil
• what charge do alpha particles have 


  a positive charge
• what happened during the alpha scattering experiment 


  most particles went straight through

  sometimes it was deflected

  sometimes it bounced straight back
• what did most the alpha particles passing through mean 


  that the atom was mostly empty space
• what did some of the alpha particles being deflected mean about the atom 


  the center of the atom must have a positive charge
• what did some of the alpha particles bouncing back mean for the atom


  the center must contain a great deal of mass
• Neils Bohr said electrons orbit the nucleus at fixed distances
• James Chadwick discovered the nucleus contained neutrons
• order of discovery of sub atomic particles 


  electron

  proton

  neutron
• what is the size of the radius on an atom 


  0.1 nanometers
• what is the relative charge of a proton 


  +1
• what is the relative charge of a neutron 


  0
• what is the relative charge of an electron 


  -1
• what was the problem with Newlands octaves 


  because he stuck purely to atomic weight sometimes elements with very different properties were grouped together
• if you order by atomic weight elements can be in the wrong order due to isotopes
• properties of group 1 metals 


  soft

  low melting points

  low density
• how do group 1 elements react with oxygen chlorine and water 


  very rapidly
• properties of transition metals 


  hard and strong

  high melting points

  high density

  less reactive than G1 metals

  form positive ions with different charges

  form coloured compounds

  used as catalysts
• all halogens are covalently bonded
• melting and boiling points of halogens increase as you go down the group
• noble gases have full outer shells
• noble gases are unreactive and dont easily form molecules
• the boiling points of noble gases increase as you go down the group
• how does lithium react with oxygen 


  burns with a red flame and produces a white solid
• hoe does sodium react with oxygen 


  burns with an orange flame and produces a white solid
• how does potassium react with oxygen 


  lilac flame ( large pieces )

  make solid straight away ( small pieces )
• how does lithium react with water 


  fizzes and gradually disappears
• how does lithium react with chlorine 


  white powder is produced
• how does sodium react with water 


  fizzes rapidly , melts into a ball , disappears quickly
• how does sodium react with chlorine 


  burns with a bright yellow flame

  clouds of white powder are produced
• how does potassium react with water 


  ignites with sparks, lilac flame

  disappears quickly
• how does potassium react with chlorine 


  same as sodium but more vigorous
• why does reactivity of group 7 elements decrease as you go down the group 


  . halogens react by gaining an electron

  .the number of shells of electrons increases as you go down the group

  .the element will be less able to attract electrons from other elements

  . cant react as easily
• group 1 metals all react with chlorine to form a white precipitate
• why are atoms electrically neutral 


  have the same number of protons and electrons
• what is the radius of the nucleus of an atom 


  1 x 10(-14) m