The Periodic Table

• How is the modern periodic table ordered?

  By atomic number.
• How were the early lists of elements ordered?

  By atomic mass.
• Why did Mendeleev swap the order of some elements?

  To group them by their chemical properties.
• Why did Mendeleev leave gaps in his periodic table?

  Leave room for the elements that had not yet been discovered
• Why do elements in a group have similar chemical properties?

  Have the same number of electrons in their outer shell.
• Where are metals and non-metals located on the periodic table?

  Metals = Left Non Metals = Right
• What name is given to the group 1 elements?

  Alkali metals.
• What name is given to the group 0 elements?

  Noble gases.
• What name is given to the group 7 elements?

  Halogens.
• Why are alkali metals named this?

  They are metals that react with water to form and alkali.
• Give the general equation for the reaction of alkali metals with oxygen.

  Metal + Oxygen = Metal Oxide
• Give the general equation for the reaction of alkali metals with chlorine.

  Metal + Chlorine = Metal Chloride
• Give the general equation for the reaction of alkali metals with water.

  Metal + Water = Metal Hydroxide + Hydrogen
• How does the reactivity of the alkali metals change down the group?

  Increases (more reactive)
• Why does the reactivity of the alkali metals increase down the group?

  They are larger atoms so the outermost electron is further from the nucleus meaning there are weaker electrostatic forces of attraction and more shielding between the nucleus and the outer electron and it is easier to lose the electron.
• Give the formulae of the first 4 halogens.

  F2 - florine

  Cl2 - chlorine

  Br2 - bromine

  I2 - iodine
• How do the melting points of the halogens change down the group?

  Increase (higher melting point)
• How does the reactivity of the halogens change down the group?

  Decrease (less reactive)
• Why does the reactivity of the halogens decrease down the group?

  They are larger atoms so the outermost shell is further from the nucleus meaning there are weaker electrostatic forces and more shielding between the nucleus and outer shell and it is harder to gain the electron
• What is a displacement reaction?

  When a more reactive element takes the place of a less reactive one in a compound.
• Why are the noble gases inert (unreactive)?

  They have full outer shells so they don't need to lose or gain electrons.
• How do the melting points of the noble gases change down the group?

  Increase (higher melting point)
• Name all of the properties of metals

  Density- high

  Strength- strong

  Malleable or Brittle- malleable

  Conduction of heat- good

  Conduction of electricity- good
• Name all of the properties of non metals

  Density- low

  Strength- weak

  Malleable or Brittle- brittle

  Conduction of heat- poor (they are insulators)

  Conduction of electricity- poor (they are insulators apart from graphite)