Chemistry: Noble Gases and Alkali Metals

What happens to the reactivity of halogens as you move down Group 7?

When chlorine gas reacts with sodium bromide, what color change would you expect to observe?

Which statements about halides are true?

Which halogen would most likely displace iodine from potassium iodide?

What trend occurs with the melting and boiling points of Group 7 elements as you go down the group?

What distinguishes noble gases from other elements in the periodic table?

Which statement about Group 1 metals is correct?

What happens to the reactivity of alkali metals as you move down the group?

What is the nature of the compounds formed by alkali metals when they react with non-metals?

What characterizes the boiling points of noble gases as you go down the group?

What kind of solutions do alkali metals produce when dissolved in water?

What do halogens have in common regarding their electron configuration?

What is a common physical property of halogens?

Noble Gases

Elements in Group 0 of the periodic table
Unreactive
Do not easily form molecules
Stable electron arrangements
Boiling points increase with increasing relative atomic mass

Group 1: Alkali Metals

Elements in Group 1
One electron in their highest energy level
Low density (first three are less dense than water)
Stored under oil to prevent reaction with oxygen or water
React with water to release hydrogen and form alkaline solutions
React vigorously with water, fizzing and moving around on the surface
Examples: 2Na + 2H₂O → 2NaOH + H₂

Reactions of Group 1

React in a similar way
One electron in their outer shell
React with non-metals to form ionic compounds (e.g., 2Na + Cl₂ → 2NaCl)
White solids that dissolve in water to form colourless solutions.

Increasing Reactivity Down Group 1

Reactivity increases down the group
Larger atoms, outer electron further from the nucleus
Outer electron more easily lost

Group 7: Halogens

Elements in Group 7
Seven electrons in their highest energy level
Coloured vapours (toxic)
Form ionic salts with metals (e.g., chloride, bromide, iodide)
Form molecular compounds with non-metals
Molecular structure (Cl₂, Br₂, I₂)

Trends in Group 7

Down the group:
- Higher relative molecular mass
- Higher melting and boiling points (due to increased intermolecular forces)
- Less reactive

Displacement Reactions (Group 7)

More reactive halogens can displace less reactive halogens from their salts in aqueous solution
Examples:
- Cl₂ + 2 NaBr → Br₂ + 2 NaCl
- Cl₂ + 2 Nal → I₂ + 2 NaCl
- Br₂ + 2 Nal → I₂ + 2 NaBr
Colour changes can indicate the reaction (e.g., orange Br₂, brown I₂)

Decreasing Reactivity Down Group 7

Reactivity decreases down the group
Larger atoms, outer shell electrons further from nucleus
Outer electrons less strongly attracted to nucleus
Outer electrons less easily gained

Test your knowledge on the properties and reactions of noble gases and alkali metals. This quiz covers essential concepts such as reactivity trends, group characteristics, and chemical reactions. Perfect for chemistry students looking to reinforce their understanding of these important elements.