📖 In-Depth Theory
Comparing Transition Metals with Group 1
Transition metals occupy the central block of the periodic table (periods 4–6, groups 3–12).
Common examples: iron (Fe), copper (Cu), zinc (Zn), chromium (Cr), titanium (Ti), nickel (Ni), cobalt (Co), gold (Au), silver (Ag), platinum (Pt).
COMPARISON WITH GROUP 1 (ALKALI METALS):
Property | Transition metals | Group 1 metals
Melting point | HIGH (e.g. iron 1538°C) | LOW (e.g. sodium 98°C)
Density | HIGH (e.g. iron 7.8 g/cm³) | LOW (e.g. lithium 0.5 g/cm³)
Hardness | HARD and strong | SOFT (can be cut with a knife)
Reactivity with water | LOW or none | HIGH (vigorous reaction)
Reactivity with oxygen | LOW (often need heating) | HIGH (rapidly tarnish or burn)
Strength | High tensile strength | Low strength
Group 1 metals are so reactive they must be stored under oil to prevent oxidation.
Transition metals are generally much less reactive and much more mechanically useful.
Typical Properties of Transition Metals
Transition metals share several characteristic properties:
1. HIGH DENSITY AND HARDNESS:
Much denser and harder than Group 1 metals.
Makes them useful as structural materials.
Iron: used in construction, steel-making.
Titanium: extremely strong and light, used in aircraft.
2. HIGH MELTING POINTS:
Most transition metals have melting points above 1000°C.
Exception: mercury (Hg) is a liquid at room temperature.
Makes them suitable for high-temperature applications.
3. FORM COLOURED COMPOUNDS:
Transition metal ions produce characteristically coloured compounds and solutions.
Copper(II) sulfate: blue. Iron(II) sulfate: pale green. Iron(III) chloride: yellow/brown.
Potassium manganate(VII): purple. Potassium dichromate: orange.
This colour arises from the d-electrons of the transition metal ion.
4. ACT AS CATALYSTS:
Transition metals and their compounds are widely used as catalysts.
Iron: catalyst in Haber process (making ammonia).
Nickel: catalyst in hydrogenation of vegetable oils (making margarine).
Platinum/rhodium: catalytic converters in car exhaust systems.
Manganese(IV) oxide: catalyst for decomposition of hydrogen peroxide.
Vanadium(V) oxide: catalyst in Contact process (making sulfuric acid).
5. VARIABLE OXIDATION STATES:
Transition metals can form ions with different charges.
Iron: Fe²⁺ (iron(II)) and Fe³⁺ (iron(III)).
Copper: Cu⁺ (copper(I)) and Cu²⁺ (copper(II)).
Manganese: Mn²⁺, Mn⁴⁺, Mn⁷⁺ (in permanganate).
This is why they can act as effective catalysts — they can change oxidation state during a reaction.
Uses of Transition Metals
The properties of transition metals make them essential materials:
IRON AND STEEL:
Iron is the most widely used transition metal.
Pure iron is soft — alloyed with carbon and other elements to make steel.
Steel: high tensile strength, used in construction, vehicles, tools.
Stainless steel (with chromium and nickel): rust-resistant, used in cutlery and surgical instruments.
COPPER:
Good electrical and thermal conductor.
Used in electrical wiring, plumbing pipes, heat exchangers.
Copper alloys: bronze (Cu + Sn), brass (Cu + Zn).
TITANIUM:
Very strong, low density, excellent corrosion resistance.
Used in aircraft, spacecraft, artificial joints, dental implants.
NICKEL:
Catalyst in food industry (hydrogenation of oils).
Used in alloys (stainless steel, nichrome heating wire).
PLATINUM:
Excellent catalyst — catalytic converters, laboratory catalysts.
Jewellery — resistant to corrosion.
GOLD AND SILVER:
Resistant to corrosion — jewellery, electrical contacts, photography.
⚠️ Common Mistake
Transition metals have HIGH melting points, HIGH density and are HARD — the opposite of Group 1. Group 1 are soft, low melting point, low density and very reactive. Don't confuse their properties. Mercury is the exception among transition metals — it is a liquid at room temperature.