Atomic structure and the period

• What is the arrangement, movement and energy of a solid?


  Tightly packed, all touching, regular arrangement

  Vibrate on spot

  Low kinetic energy
• What is the arrangement, movement and energy of a liquid?


  Close tighter, no regular pattern

  Flow easily, over one another, takes shape of container

  More kinetic energy than a solid
• What is the arrangement, movement and energy of a gas?


  Very separated, no regular arrangement, takes shape of container

  Move freely at high speeds

  Lots of kinetic energy
• Gas to liquid


  condensation
• Liquid to solid


  freezing
• Solid to liquid


  melting
• Liquid to gas


  evaporation
• Gas to solid


  deposition
• Solid to gas


  sublimation
• Radius of an atom

  1x10^-10m
• What is the nucleus' size in relation to the atom?

  1/10000
• How has the atom developed over time?


  Democritus claimed an atom cannot be split

  John dalton stated that atoms were tiny particles

  Thompson discovered electrons and proved atoms can be split

  Rutherford developed the nuclear model with a concentrated mass in the nucleus with electrons orbiting

  Bohr discovered electrons travel along shells

  Chadwick devised an experiment show show the existence of neutrons
• Describe the alpha particle scattering experiment


  Rutherford

  Positive alpha particles were fired at gold foil

  Most passed through

  Showing the atom is most empty space

  Some very deflected and some bounced back

  Repelled by a positive nucleus

  Small dense positively charged nucleus at centre
• How to calculate the number of protons


  equals atomic number
• How to calculate the number of electrons

  equals the number of protons
• How to calculate the number of neutrons

  mass number - atomic number
• Structure of the atom

  protons and nuetrons are located in the nucleus, electrons are distributed about the nuclus to make the atom
• Relative mass of a proton

  1
• Relative mass of neutron

  1
• Relative mass of electron

  Almost 0
• Charge of proton


  +1
• Charge of neutron


  0
• Charge of electron


  -1
• What is the atomic number?

  number of protons
• What is the mass number

  Number of protons and neutrons
• What is an isotopes


  Atoms of the same element can have different numbers of neutrons
• What is the relative atomic mass?

  An average mass of isotopes making up an element and how much of each element there is.
• How are elements arranged on the periodic table?

  By atomic number in groups and periods
• How do you deduce the electronic configuration of the first 20 elements?


  Group - electrons in outer shell

  Period - amount of shells

  
  

  2.8.8.2
• How to known is an element is a metal or non metal from the period table?

  Step from boron
• How to calculate relative atomic mass


  total mass of atoms/total number of atoms
• How do isotopes of an element differ?

  Because isotopes of an element have different numbers of neutrons, they also have different mass numbers.
• Isotopes all have similar what ?

  Chemical properties
• What does an element look like?

  Atoms of uniform look
• What does compound mean?

  Two or more elements combined together
• What is a mixture


  A combination of two or more substances that are not chemically combined
• Difference between metals and non metals


  Metals -

  high melting point

  ductile

  good conductor

  magnetic

  shiny

  
  

  Non metals -

  low melting point

  brittle

  poor conductors

  low density
• Properties of metals


  Shiny luster

  high malleability

  High ductility

  electrical conductor

  thermal conductivity.
• Properties of non metals


  Not malleable

  Not ductile

  not shiny

  poor conductors of heat and electricity

  brittle
• How was the periodic table developed by Mendeleev?


  Ordered in atomic mass

  Left gaps where nothing fit

  Followed a repeated pattern