Properties of Transition Metals vs Group 1 Elements Revision Notes | GCSE AQA Higher Chemistry

1. Two Very Different Types of Metal

You might think all metals are similar, but compare a copper coin with a piece of sodium. The copper is hard, dense and doesn't react with air. Sodium is so soft you can cut it with a knife, floats on water, and bursts into flames when exposed to air.

These dramatic differences come down to where the metals sit in the periodic table. Group 1 metals (like sodium and potassium) behave completely differently to transition metals (like iron, copper and zinc). Understanding why gives you the key to predicting how any metal will behave.

2. Melting Points - Why Transition Metals Stay Solid

Here's where the differences become dramatic. Transition metals have melting points typically above 1000°C. Iron melts at 1538°C, copper at 1085°C. Group 1 metals? Sodium melts at just 98°C - you could melt it in boiling water.

This happens because of metallic bonding strength. Transition metals have more electrons available for bonding and smaller atomic radii. This creates stronger attractions between the metal atoms and the 'sea' of delocalised electrons. Group 1 metals have just one outer electron each and much larger atoms, so the bonding is weaker.

3. Density and Strength - The Physical Differences

Pick up a copper pipe and a similar-sized piece of sodium (don't actually do this - sodium is dangerous!). The copper feels heavy and solid. Sodium would feel surprisingly light and you could dent it with your fingernail.

Transition metals are typically 7-9 times denser than water. Iron has a density of 7.9 g/cm³, copper is 8.9 g/cm³. Group 1 metals are much less dense - sodium is only 0.97 g/cm³, which is why it floats on water. Lithium is even less dense at 0.53 g/cm³.

The same bonding differences explain hardness and strength. Transition metals form strong, rigid structures. Group 1 metals are soft because their weak metallic bonding allows layers of atoms to slide past each other easily.

4. Reactivity Patterns - The Chemical Behaviour

This is where Group 1 metals show their true nature. They're incredibly reactive - sodium reacts violently with water, producing hydrogen gas and enough heat to ignite it. Potassium reacts very vigorously, igniting the hydrogen gas produced and burning with a lilac flame.

Transition metals are far less reactive. Iron rusts slowly in damp air over months or years. Copper develops a green patina over decades. Some transition metals like gold and platinum barely react at all - that's why they're used in jewellery.

Worked example: Comparing Reactions with Water

Compare what happens when sodium and iron react with water

1. $2Na + 2H_2O \rightarrow 2NaOH + H_2$ — Violent reaction, hydrogen gas produced, heat generated
2. $4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3$ — Very slow reaction, needs oxygen present, forms rust
3. Sodium: seconds Iron: months to years — Group 1 metals react instantly, transition metals react slowly

Answer: Group 1 metals react violently and quickly with water, while transition metals react very slowly and often need oxygen present

With oxygen, the pattern continues. Group 1 metals tarnish instantly in air and burn with bright flames. Transition metals form oxide layers slowly, and many need heating to react with oxygen.

Halogens (Group 7) also show this pattern. Sodium reacts explosively with chlorine gas. Iron needs heating and forms iron chloride slowly. The more reactive the metal, the more vigorous the reaction.

5. Why These Differences Matter - Practical Applications

These property differences explain why we use different metals for different jobs. You'll never see a sodium bridge or a lithium car engine. The low melting points, low strength and high reactivity of Group 1 metals make them unsuitable for structural uses.

Instead, we use transition metals for construction, tools and machinery. Iron and steel for buildings and cars. Copper for electrical wiring (good conductor, doesn't corrode easily). Titanium for aircraft (strong but light). Their high melting points and strength make them perfect for these applications.

Group 1 metals do have uses, but they're based on their reactivity. Sodium is used in street lamps (burns with a bright yellow light) and in some nuclear reactors as a coolant. But these applications require careful handling because of the high reactivity.

6. Exam Technique - Getting Full Marks on Comparison Questions

Exam questions often ask you to compare transition metals with Group 1 metals. The key is to be specific about both groups and explain the differences, not just list properties.

Common exam mistake: Writing 'transition metals are stronger' without comparison. Better: 'Transition metals like iron are much stronger than Group 1 metals like sodium, which can be cut with a knife.'

For 6-mark questions, structure your answer: state the property difference, give examples with data, explain the scientific reason (bonding/electron structure), then link to practical applications.

Group 1 metals react readily with halogens to form white ionic salts such as sodium chloride because they lose one electron easily. Transition metals also form chlorides and other halides, but they are generally less reactive, often form coloured compounds, and can form ions with different charges.