The Transition Metals

The Transition Metals

Chapter 3: Patterns and Properties of Metals

Overview

• Transition elements (or transition metals) are the block of 30 elements located in the middle of the Periodic Table.

• They are all metals, and include most of the metals we use every day – such as iron, tin, copper, and silver.

• They are much less reactive than the metals in Group I and II.

Multiple Choice

Where are the transition metals placed in the periodic table?

• On the left-hand side

• On the right-hand side

• In the central block

• Can't be found

Multiple Choice

Which element does not belong to transition elements?

• copper

• iron

• sodium

• zinc

Major Properties of Common Metals

• Hard and strong

• High melting points

• High densities

• Good conductors of heat and electricity

• Malleable (can be hammered into different shape)

• Ductile (can be drawn into wires)

The Distinctive Properties of Transition Metals

• Many of their compounds are coloured, (e.g. CuSO₄ - blue, KMnO₄ - purple)

• These metals often show more than one valency - they form more than one type of ion. (e.g. iron can form Fe²⁺ and Fe³⁺)

• The metals or their compounds often make useful catalysts. (e.g. Fe as a catalyst in making ammonia, and V₂O₅ as a catalyst in making sulfuric acid)

• A few of the metals are strongly magnetic (iron, cobalt and nickel).

Multiple Choice

Which property of transition metals is different from that of elements in group 1?

• Good conductors of electricity

• Good conductors of heat

• High melting points

• Very reactive

Multiple Choice

Which of these metals is the least hard?

• Chromium

• Nickel

• Sodium

• Iron

Coloured Compounds

• The compounds of the metals in Group I, II and II are generally white solids. They give colourless solutions if they dissolve in water.

• In contrast, the compounds of the transition elements are often coloured and produced coloured solutions when dissolved.

Multiple Choice

Which of these compounds is green?

• Nickel(II) chloride

• Calcium chloride

• Sodium chloride

• Potassium chloride

Variable Oxidation States (Valency)

• The metals in Group I and II have single oxidation state (valency).

• The metals in Group I have valency of 1. They tend to lose 1 electron to form +1 ions (e.g. Li⁺, Na⁺, K⁺).

• The metals in Group II have valency of 2. They tend to lose 2 electrons to form +2 ions (e.g. Mg²⁺, Ca²⁺).

• The transition metals have variable oxidation states. For example, iron can form Fe²⁺ and Fe³⁺.

Multiple Choice

The transition elements have multiple oxidation states.

• TRUE

• FALSE

Catalytic Properties

• Catalysts are substances that speed up a chemical reaction without themselves being used up or changed at the end of the reaction.

• Many of the important industrial catalysts are either transition elements or their compounds, for example iron in the Haber process (making ammonia); and V2O5 in the Contact process (making sulfuric acid).

Multiple Choice

Which of these elements is a catalyst for the production of ammonia?

• Iodine

• Iron

• Sodium

• Magnesium

Magnetic Properties

Three of the first row of transition elements are strongly magnetic. They are iron, cobalt and nickel. The Earth's magnetic field is produced by the liquid and solid iron and nickel in the outer and inner core of the planet.

Multiple Choice

Element X has a melting point of 1453°C, element Y has a melting point of 1083°C, and element Z has a melting point of 63.4°C. Which element is in group 1?

• X

• Y

• Z