8.5The Periodic Table
Noble gases — Combined Science 0653 - Chemistry Revision Notes & Topical Questions
5 min read 13 parts Lesson 8 of 8 1 quiz
Lesson summary
8.5 Noble gases — COMBINED SCIENCE (CHEMISTRY) notes: Describe the noble gases as unreactive, monatomic gases and explain this using electronic configuration.Group VIII — the noble gases are at the far right of the Periodic Table.Members — helium, neon, argon, krypton and xenon.N…
- Non-metals
- Colourless gases
- Low melting and boiling points
- Full outer shell
- No need to change
- Monatomic — they exist as single atoms
Section 1 of 13Position and members
Position and members
Group VIII
- Group VIII the noble gases are at the far right of the Periodic Table.
Members
- Members helium, neon, argon, krypton and xenon.
Section 2 of 13Physical properties
1Non-metals
- Non-metals the noble gases are non-metals.
2Monatomic
- Monatomic they exist as single atoms.
3Colourless gases
- Colourless gases all are colourless gases at room temperature.
4Low melting and boiling points
- Low melting and boiling points very low, because only very weak forces act between the atoms.
Section 3 of 13Electronic configurations
| Noble gas | Electronic configuration |
|---|---|
| Helium | 2 |
| Neon | 2,8 |
| Argon | 2,8,8 |
| Krypton | 2,8,18,8 |
| Xenon | 2,8,18,18,8 |
Section 4 of 13Why the noble gases are unreactive
Full outer shell
- Full outer shell each has a full outer shell of electrons.
- (two for helium and eight for the others)
No need to change
- No need to change they have no need to gain, lose or share electrons.
Stable
- Stable the configurations are extremely stable, so noble gases do not easily form bonds with other elements.
Section 5 of 13Uses of the noble gases
| Gas | Use | Property used |
|---|---|---|
| Helium | Balloons and airships | Very light and unreactive |
| Neon | Advertising signs | Glows when electricity passes through |
| Argon | Filament lamps and inert atmosphere for welding | Unreactive |
Section 6 of 13More from the specification
More from the specification
Low temperature noble gas solid
- Low temperature noble gas solid weak London dispersion forces condense noble gases into liquids only at cryogenic temperatures before freezing into a crystalline solid.
Noble gas inertness (Group 0)
- Helium, neon, and argon have fully occupied valence shells, making them chemically unreactive and monatomic.
Density trends down Group 0
- Density and boiling point increase progressively down the group from helium to radon.
Practical applications
- Argon is used as an inert shielding gas in welding, and helium is used in airships and balloons due to low density and non-flammability.
Group trends comparison
- Unlike halogens which undergo displacement reactions in aqueous potassium solutions, noble gases form no ionic compounds.
- (chlorine, bromine, iodine)
Aqueous
- Dissolved in water.
Displacement
- A reaction in which a more reactive element takes the place of a less reactive one in a compound.
Transition elements
- The central block of metals between Group II and Group III.
Displacement reaction
- A more reactive element replaces a less reactive one in a compound
Alkali metals
- The Group I metals, which form alkaline solutions with water.
Physical property
- A property observed or measured without changing the material.
Halogens
- Group 17 non-metals that form diatomic molecules.
Halogen
- A Group VII non-metal with seven outer electrons.
Trend
- General pattern down a group or across a period.
Observation
- What is seen, heard, smelt or measured
Section 7 of 13Electron arrangements and stability
Full outer shells
- He 2, Ne 2,8, Ar 2,8,8, Kr 2,8,18,8 and Xe 2,8,18,18,8.
Inertness
- Inertness a full outer shell means no tendency to gain, lose or share electrons, so no compounds form under normal conditions.
Section 8 of 13Comparing with reactive elements
| Element | Configuration | Behaviour |
|---|---|---|
| Sodium | 2,8,1 | Loses one electron to reach 2,8 |
| Chlorine | 2,8,7 | Gains one electron to reach 2,8,8 |
| Argon | 2,8,8 | Already full, so unreactive |
Section 9 of 13Physical trends
Physical trends
Low boiling points
- Low boiling points helium boils at about −269 °C, because only very weak forces act between atoms.
Down the group
- Down the group boiling points rise slightly as the atoms get larger.
Monatomic
- Monatomic each particle is a single atom.
Section 10 of 13Uses that follow from inertness
Helium
- Helium fills balloons and airships.
Neon
- Neon is used in advertising signs.
Argon
- Argon is used in filament lamps and as an inert atmosphere for welding.
Section 11 of 13More from the specification
More from the specification
Unreactive Nature of Group 0 Noble Gases
- Noble gases (such as helium, neon,
- and argon) possess completely filled valence electron shells, conferring extreme chemical inertness and very low melting and boiling points that increase gradually down the group.
Halogen Displacement Reactions in Aqueous Solution
- Group 7 halogens exhibit decreasing oxidizing strength down the group: adding chlorine water to a potassium bromide or potassium iodide solution oxidises colourless halide ions to orange bromine or dark brown iodine.
Physical Properties of Group 1 Alkali Metals vs. Transition Metals — Group 1 alkali metals (such as potassium) have low densities, low melting points,
- and react vigorously with water,
- whereas transition metals have much higher melting points, higher densities,
- and lower chemical reactivity.
Coloured Compounds Formed by Transition Elements
- Unlike the white compounds formed by Group 1 metals, transition metals characteristically form brightly coloured ionic compounds and coordination complexes in aqueous solution.
Periodic
- Describing properties that repeat at regular intervals along the table
Observation
- What is seen, heard, smelt or measured
Aqueous
- Dissolved in water.
Displacement
- A reaction in which a more reactive element takes the place of a less reactive one in a compound.
Transition elements
- The central block of metals between Group II and Group III.
Displacement reaction
- A more reactive element replaces a less reactive one in a compound
Alkali metals
- The Group I metals, which form alkaline solutions with water.
Property
- A feature that describes what a substance is like and what it does.
Metal
- An element with a lattice of positive ions in a sea of delocalised electrons, usually shiny, conductive and malleable.
Halogens
- Group 17 non-metals that form diatomic molecules.
Melting
- Solid to liquid at the melting point, absorbing energy.
Halogen
- A Group VII non-metal with seven outer electrons.
Section 12 of 13Key terms
| Term | Meaning |
|---|---|
| Noble gas | Unreactive Group VIII element. |
| Monatomic | Made of single atoms. |
| Full outer shell | Outer shell with its maximum number of electrons. |
| Inert | Unreactive. |
| Electronic configuration | Number of electrons in each shell. |
| Term | Meaning |
|---|---|
| Monatomic | Made of single atoms. |
| Inert | Unreactive. |
| Full outer shell | Maximum number of electrons in the outer shell. |
| Boiling point | Temperature at which a liquid boils. |
| Noble gas | Group VIII element. |
Section 13 of 13Exam technique
1
Describing the noble gases as diatomic — they are monatomic.
2
Saying helium has eight outer electrons — it has two.
3
Saying noble gases have high boiling points.
4
Confusing Group VIII with Group I.
1
Describing noble gases as diatomic.
2
Stating helium has eight outer electrons.
3
Saying noble gases have high boiling points.
4
Saying noble gases form many compounds.
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