Atomic structure and the periodic table

• Who created the first model of the atom

  • John Dalton
• What was John Daltons model?

  • he believed matter was made of tiny particles called atoms
  • imagined then as tiny spheres that can’t be divided
• Who discovered the plum pudding model

  JJ Thompson
• Describe the plum pudding model

  • ball of positive charge with negative electrons embedded into it
• Who created the Nucleat model?

  Ernest rutherford
• What experiment led to the nuclear model?

  Rutherford’s alpha gold experiment
• What happened when the positive alpha particles were fired at the thin gold foil?

  • most went straight through but a few scattered in different directions
• What conclusions were drawn from the gold foil experiment

  • mass atom concentrated at centre (nucleus)
  • nucleus positively charged
• What adaption did Neil’s Bohr make to the nuclear model?

  • electrons orbit nucleus in shells at fixed distances from the nucleus
• what was discovered after the electron

  the proton
• what was discovered after the proton

  neutron
• Who discovered the neutron

  James Chadwick
• What is the radius of an atom

  1 x 10^-10
• What is the radius of a nucleus

  1 x 10^-14
• What is the relative mass of a proton

  1
• what is the relative mass of a nuetron

  1
• what is the relative mass of an electron

  very small (nearly zero)
• What is the atomic number

  number of protons
• Atoms have equal …

  protons and electrons
• What is an isotope?

  Atoms of the same element with different number of nuetrons
• How did earth scientists classify elements

  by atomic weight
• what is atomic weight equivalent to?

  relative atomic mass
• Charecteristics of early periodic tables

  • incomplete
  • placed in groups with elements not similar to them
• how did mendeleev arrange elements?

  By increasing atomic mass.
• What did Mendeleev’s periodic table have?

  • Gaps for undiscovered elements.
  • elements placed in groups with similar properties
• What did Mendeleev predict using gaps

  he predicted the properties of undiscovered elements
• What made it possible to explain why the order based on atomic weight wasn’t wasn’t always correct

  the knowledge of isotopes
• how are elements arranged in the modern periodic table

  • in periods in order of increasing atomic number
• Why is it called the periodic table

  • because similar properties occur at regular intervals
• Properties of metals

  • good conductor of electricity + heat
  • high melting + boiling points
  • shiny
  • high density
  • malleable
  • ductile
• Properties of non-metals

  • poor conductor of electricity + heat
  • dull
  • low density
  • brittle
• what are group 0s also known as

  noble gases
• What boiling points do group 0 have

  low
• What happens to the boiling point as you go down the group

  increases
• Why does the boiling point increase as you go down group 0

  • atom gets larger
  • intermolecular forces get stronger
  • more energy needed to overcome these forces
• noble gases are …

  inert (very unreactive)
• Why are group 0 elements inert?

  because they have a full outer shell
• What are group 1 metals also known as?

  Alkali metals
• Physical properties of group 1

  • soft (can be cut with a knife)
  • relatively low melting points
  • low densities
• What happens to the melting point as you go down the group

  decreases