Group 0 (OCR Gateway GCSE Chemistry)

• The elements in Group 0 of the periodic table are called the noble gases
• They are all non-metal, monatomic (exist as single atoms), colourless, non-flammable gases at room temperature
• The Group 0 elements all have full outer shells of electrons; this electronic configuration is extremely stable
• They do not need to lose or gain electrons like other elements which makes them unreactive 
• Other than helium which has 2 electrons in its outer shell, the noble gases have eight valence electrons (which is why you may see this group labelled “group 8”)
• Electronic configurations of the Noble gases:
  • He = 2
  • Ne = 2, 8
  • Ar =  2, 8, 8
  • Kr =  2, 8, 18, 8
  • Xe = 2, 8, 18, 18, 8

The periodic table highlighting the noble gases - they occupy the group furthest to the right 

Uses of Group 0 Elements 

• Although chemically inert, the noble gases do have several applications and uses
• Helium is used for filling balloons and weather balloons as it is less dense than air and does not burn
• Neon, argon, and xenon are used in advertising signs
• Argon is used to provide an inert atmosphere for welding
• Argon is also used to fill light bulbs, as like the other noble gases, it has the unusual property of glowing brightly when a high potential difference is applied to the gas under low pressure

Physical Properties

• As with other groups, there are trends in the physical properties of the noble gases
• The noble gases have very low melting and boiling points
• They show an increase in boiling point as we move down the group due to an increase in the relative atomic mass (the atoms get larger as you move down the group)
• This leads to an increase in intermolecular forces between atoms, increasing the amount of energy needed to overcome these forces to change state
• Elements further down the group have higher boiling points but these still lie below 0 ºC
• Helium has the lowest boiling point of all known elements at -269 ºC, while radon boils at around -60 ºC

This graph shows the trend in boiling point of the noble gases

• Since the Group 0 elements are all gases at room temperature, individual atoms are widely spaced apart, giving them low densities
• Their density increases as you move down the group
• Elements further down the group would be expected to have higher densities
• Helium is the lightest noble gas and radon is the heaviest

This graph shows the trend in the densities of the noble gases