the periodic table

• Group 1 elements


  • Lithium
  • Sodium
  • Potassium
  • Rubidium
  • Cesium
  • Francium
• Group 1 elements react with

  1. Oxygen

  2. Chlorine

  3. Water
• Reactions of Group 1 elements

  • Lithium + oxygen → lithium oxide
  • Lithium + chlorine → lithium chloride
  • Lithium + water → lithium hydroxide + hydrogen
• Alkali metals


  Group 1 elements that react with water to form an alkali (a solution of their metal hydroxide)
• Group 1 elements


  • They all have one electron in their outer shell
  • They are very reactive because they only need to lose one electron to react
  • Reactivity increases down Group 1 because the atoms increase in size, the outer electron is further away from the nucleus, and there are more shells shielding the outer electron from the nucleus, so it is easier to lose the one outer electron
  • The melting point and boiling point decreases down Group 1
• The reaction of Group 1 metals with water is rather spectacular, with the tiny lumps of metal bursting into flames when they hit the water and whizzing around, fizzing as the hydrogen is released
• Group 7 elements (halogens)


  • Fluorine
  • Chlorine
  • Bromine
  • Iodine
• Halogens


  Group 7 elements that exist as molecules made up of pairs of atoms
• Group 7 elements


  • Reactivity decreases down the group because the atoms increase in size, the outer shell is further away from the nucleus, and there are more shells between the nucleus and the outer shell, so it is harder to gain the one electron to fill the outer shell
  • Melting point and boiling point decreases down the group
• Group 7 displacement


  More reactive Group 7 elements can take the place of less reactive ones in a compound
• 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 elements with similar properties together. To group them by their chemical properties.
• Why did Mendeleev leave gaps in his Periodic Table?

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

  have the same number of electrons in the outer shell
• Where are metals and non-metals located on the Periodic Table?

  Metals are located on the left side of the Periodic Table, while non-metals are located on the right side.
• What name is given to the group 1 elements?

  Alkali metals
• Why are alkali metals named this?


  Because they form alkaline solutions when they react with water.
• Give the general equation for the reactions of alkali metals with oxygen, chlorine, and water. +

  metal + oxygen = metal oxide

  metal + chlorine = metal chloride

  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 done 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 outer electron, and it is easier to lose the electron.
• What is the name given to the group 7 elements?

  Halogens
• Give the formulae of the first four halogens.

  F2, Cl2, Br2, I2
• 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 of attraction and more shielding between the nucleus and outer shell, and it is harder to gain an 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?

  they have full outer shells so do not need to lose or gain elements.
• How do the melting points of the noble gases change down the group?

  increase (higher melting point)
• Periodic Table


  A table that lists approximately 100 elements and has changed a lot over time as scientists have organised the elements differently
• The first lists of elements, Mendeleev's Periodic Table, and the modern Periodic Table have a number of differences in how they list the discovered elements
• Group 1 elements


  React with water to form an alkali
• Group 1 elements react with

  • Oxygen
  • Chlorine
  • Water
• Group 1 properties


  They are very reactive because they have no gaps all elements up to a certain electron to react
• As the atomic number increases down the group

  Reactivity increases
• First lists of elements

  Organised by atomic mass
• Mendeleev's Periodic Table


  Normally organised by atomic mass but some elements were swapped around
• Modern Periodic Table


  Organised by atomic number
• First lists of elements

  • Had gaps left for undiscovered elements
  • No clear distinction between metals and non-metals
  • Some elements grouped inappropriately
  • Incomplete with no explanation for why
• Mendeleev's Periodic Table


  • Some elements had to be swapped to fit in the appropriate groups