Group 1 elements are very reactive and their reactivity increases down the group.
Moving down Group 1 elements, atomic mass, density and melting points increase.
In chemical reactions, atoms of Group 1 elements lose one outer electron leaving full electron shells.
Going down Group 1, the outer electron of each element is attracted to the atomic nucleus with less force.
Group 1 metals react with water to produce alkaline solutions.

Common misconception

Pupils can confuse the trend in reactivity down the group.

The practical reacting the metals with water helps to memorably demonstrate the trend, however it is important to ensure that pupils can explain why this happens.

Keywords

Alkali metals - Alkali metals are the elements in Group 1 of the periodic table which react with water to form strongly alkaline hydroxides.
Density - Density is a measurement of mass per unit volume; how tightly packed a substance's particles are in a particular space.
Alkali metal hydroxides - Alkali metal hydroxides are soluble compounds formed when the alkali metals react with water. They form colourless solutions.

Very important that pupils can describe what they see when the alkali metals react. Good to first emphasise what is visible and then what is happening and why.

Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

Skip video

Worksheet

Download worksheet

Skip worksheet

Starter quiz

Download starter quiz

6 Questions

Q1.

Match the following symbols to their elements.

Correct Answer:Na,sodium

sodium

Correct Answer:K,potassium

potassium

Correct Answer:Rb,rubidium

rubidium

Correct Answer:Fr,francium

francium

Correct Answer:Li,lithium

lithium

Correct Answer:Cs,caesium

caesium

Q2.

Elements are said to be in the same if they are in the same column of the periodic table.

Correct Answer: group

Q3.

Place these elements in order of decreasing relative atomic mass.

1 - francium

2 - caesium

3 - rubidium

4 - potassium

5 - sodium

6 - lithium

Q4.

Elements in a group have similar physical properties. What is meant by a physical property?

Correct answer: Features that can be observed without changing the substance itself.

Features of the way a substance reacts with other substances.

Q5.

What type of category best describes Group 1 elements?

Correct answer: reactive metals

halogens

transition metals

non–metals

noble gases

Q6.

Which Group 1 element has 55 protons, 55 electrons and 78 neutrons?

Correct answer: Cs

Exit quiz

Download exit quiz

6 Questions

Q1.

What is the name given to Group 1 of the periodic table?

halogens

Correct answer: alkali metals

noble gases

transition metals

Q2.

What is the correct electron configuration of sodium?

2,1

2,8

Correct answer: 2,8,1

2,8,8,1

Q3.

Reactivity down the group for Group 1 elements.

Correct Answer: increases , goes up

Q4.

Place the following Group 1 metals in order of density, starting with the least dense element first.

1 - lithium

2 - potassium

3 - rubidium

4 - caesium

Q5.

Explain why you would expect francium to be more reactive than caesium.

Correct answer: Outer electron in francium is attracted with less force to its atomic nucleus.

Correct answer: Outer electron in caesium is attracted with more force to its atomic nucleus.

Outer proton in francium is attracted with more force to its atomic nucleus.

Outer proton in caesium is attracted with less force to its atomic nucleus.

Correct answer: Francium has more electron shells.

Q6.

What are the products of the reaction between lithium and water?

Correct answer: lithium hydroxide

lithium oxide

Correct answer: hydrogen

Correct answer: an alkaline solution

water