groups

• Noble gases


  • Group 0, all elements have full outer shells, so are unreactive
  • Exist as monatomic atoms, not molecules
  • Have low boiling points, as they do not have any bonds to break, but as you go down the periodic table, they increase, as the relative atomic masses increase
  • Have low density, but this increases as you go down the periodic table - Making them useful in balloons
• Halogens


  • Group 7, have 7 outer electrons, forming -1 charge ions
  • Form diatomic molecules
  • When a metal atom transfers its electrons to a non-metal atom, salts are formed, a compound is formed where all elements involved possess a full outer shell
  • Reactivity decreases as you go down the group, as the outer shell is further away from the nucleus, and the atoms gain more electron shells as you move down periods, and the attraction with the gained electron decreases, due to all the shells blocking the nuclear attraction forces
• Alkali metals


  • Group 1
  • Potassium - The most reactive metal, loses 1 electron in every reaction, and in its reaction with water it burns and produces a lilac flame, exploding
  • Sodium - More reactive than lithium as the outer electron is less under the influence of the nucleus, and in its reactions with water it floats onto the surface, and with oxygen it burns and produces an orange colour flame
  • Lithium - The least reactive of all of the alkali metals, burning with a red flame when reacting with oxygen, with water it floats on the surface, effervescencing hydrogen gas
• Group 1 properties


  • Reactions with water - the metal floats on the surface and melts to produce a metal hydroxide, releasing energy (exothermic) to melt the metal
  • Reactions with oxygen - The metal turns from a shiny silvery colour to dull grey as the metal forms a metal oxide
  • Reactions with chlorine - The metal reacts with chlorine to produce a metal chloride, which dissolves in water to provide a colourless solution
• Reactivity of Group 1

  • As you go down group 1, the reactivity increases, because the outer electron is further away from the nucleus, meaning that it is less under the orbital magnetic forces, weaker attraction, due to the increase of shells, meaning that the electron is easier to lose to other nuclei with stronger nuclear forces of attraction. The electron is lost to make the atom stable with a full outer shell
• What happens to reactivity as you go down Group 7 of the periodic table?

  Reactivity decreases
• Why does reactivity decrease in Group 7 as you go down the group?

  Because the electron to be gained has less attraction to the nucleus due to more electron shells
• What type of molecules do Group 7 elements form?

  Diatomic molecules
• What is formed when a metal transfers an electron to Group 7 atoms?

  Salts are formed
• What is the electron configuration of Lithium?

  2,1
• How does Lithium react with oxygen?

  It burns with a crimson flame
• What happens when Lithium is placed in water?

  It floats on the surface and effervesces hydrogen
• What is the electron configuration of Sodium?

  2,8,1
• Why is Sodium more reactive than Lithium?

  Because its outer electron has a weaker nuclear attractive force
• What happens when Sodium is placed in water?

  It floats on water, releasing enough heat to melt sodium and moves quickly across the water
• What color flame does Sodium produce when reacting with oxygen?

  Yellow/orange flame
• What is the electron configuration of Potassium?

  2,8,8,1
• How does Potassium react with water compared to Sodium?

  It has a more vigorous reaction but is similar to Sodium
• What color flame does Potassium produce when reacting with oxygen?

  Lilac flame
• How does reactivity change as you go down Group 1?

  Reactivity increases
• What happens when Group 1 metals react with chlorine?

  They make a colorless solution
• How do transition metals compare to alkali metals in terms of properties?

  • Higher density
  • Higher melting points
  • Harder and stronger
  • Lower reactivity (e.g., iron rusts slowly)
  • Can form multiple charges
  • Can form different color compounds
  • Can be used as catalysts (e.g., iron in the Haber process)