Group 0 Noadswood Science, 2016

Noble Gases To describe the properties of Group 0 – the noble gases Thursday, July 05, 2018 To describe the properties of Group 0 – the noble gases

Precise Learning The elements in Group 0 of the periodic table are called the noble gases. They are unreactive and do not easily form molecules because their atoms have stable arrangements of electrons. The noble gases have eight electrons in their outer shell, except for helium, which has only two electrons. The boiling points of the noble gases increase with increasing relative atomic mass (going down the group). Students should be able to: explain how properties of the elements in Group 0 depend on the outer shell of electrons of the atoms predict properties from given trends down the group.

Noble Gases Argon makes up about 0.9 per cent of the air It is one of a group of elements called the noble gases – the noble gases are in Group 0 of the periodic table…

Noble Gases The noble gases are all chemically un-reactive gases

Reactivity All the elements in this group have fully occupied outer shells – they are the least chemically reactive elements The stable arrangement means that the noble gases do not form chemical bonds with each other or other elements – they are monatomic (they exist as individual atoms)

Noble Gases Noble gas Main use Helium Used in balloons and airships (it is less dense than air, so balloons filled with it float) Neon Used in advertising signs, it glows when electricity is passed through it (different coloured neon lights can be made by coating the inside of the glass tubing of the lights with other chemicals) Argon Used in light bulbs (the very thin metal filament inside the bulb would react with oxygen and burn away if the bulb were filled with air instead of argon Krypton Used in lasers which are used by surgeons to treat certain eye problems and to remove birthmarks

Properties The noble gases have a full outer shell – as their outer shell is energetically stable they don’t need to give up or gain electrons to become more stable This means they are inert (they do not react) as well as being non- flammable At room temperature they are colourless monatomic gases (single atoms not bonded to anything else)

Trends The boiling points of the noble gases increase as you move down the group along with increasing relative atomic mass As you go down the group the number of electrons also increases which causes the intermolecular forces between the atoms to increase, so more energy is needed to break them (causing the boiling points to increase)

Practice Questions – Application What happens to the boiling points of the noble gases as you go down the group? Argon is an inert gas – how many electrons does it have in its outer shell and explain how this affects its reactivity The boiling point of xenon is -108oC – predict with reasoning whether krypton will be a solid, liquid or gas at this temperature

Answers They increase 8 – a full outer shell means it is inert (not needing to gain or lose any electrons) Krypton will be a gas (it is higher up the group so it will have a lower boiling point)