STUDENT SPACE · TOPIC 4

Transition elements and noble gases

Compare transition elements with Group I and explain noble-gas stability.

The essentials

Transition elements occupy the central block. Examples include iron, copper, nickel and chromium.
Many transition elements form coloured compounds. Aqueous copper(II) ions are blue.
Iron forms Fe²⁺ and Fe³⁺. In these ions, the oxidation number equals the ion charge.

Try each question before opening its hint or answer. Use paper for calculations and diagrams.

Write the formula of iron(III) oxide using Fe³⁺ and O²⁻.

Need a hint for Question 1?

Use several properties to identify a family of elements.

Check Question 1

Fe₂O₃. Two +3 ions balance three −2 ions.

Give two characteristic differences between transition elements and Group I metals.

Need a hint for Question 2?

Consider physical properties and the compounds formed.

Check Question 2

Transition elements generally have higher densities and melting points. Many also form coloured compounds and ions with variable oxidation numbers.

Explain why helium is unreactive even though it has only two electrons.

Need a hint for Question 3?

How many electrons fill the first shell?

Check Question 3

Helium’s only shell is the first shell. Two electrons fill that shell.

Use Lesson 4 in your worksheet for written practice. Your teacher will discuss those answers in class.