IGCSE Chemistry (Double) - Topic 2: Inorganic Chemistry

Which element is in Group 1 of the periodic table?

• Magnesium

• Fluorine

• Sodium

• Aluminium

Answer explanation

Sodium is the only element listed that belongs to Group 1 of the periodic table, which contains alkali metals. Magnesium (Group 2), Fluorine (Group 17), and Aluminium (Group 13) are not in Group 1.

What is a characteristic property of noble gases?

• High reactivity

• Poor conductivity

• Complete outer electron shells

• Form ionic compounds

Answer explanation

Noble gases have complete outer electron shells, making them stable and unreactive. This characteristic property distinguishes them from other elements, which often seek to gain or lose electrons to achieve stability.

What is the trend in reactivity in Group 1?

• Increases down the group

• Decreases down the group

• No trend

• Increases then decreases

Answer explanation

In Group 1, reactivity increases down the group due to the increasing atomic size and decreasing ionization energy, making it easier for the elements to lose their outermost electron.

Why do noble gases have low reactivity?

• They have full outer shells

• They have unpaired electrons

• They have low melting points

• They form diatomic molecules

Answer explanation

Noble gases have full outer shells of electrons, making them stable and unreactive. This stability is the reason they do not readily form chemical bonds with other elements.

Which of the following is a halogen?

• Potassium

• Bromine

• Argon

• Calcium

Answer explanation

Bromine is a halogen, found in Group 17 of the periodic table. Potassium and calcium are alkali and alkaline earth metals, respectively, while argon is a noble gas. Thus, bromine is the correct answer.

What happens when lithium reacts with water?

• It sinks and does not react

• It explodes immediately

• It floats and fizzes, producing hydrogen gas

• It burns with a green flame

Answer explanation

When lithium reacts with water, it floats on the surface and fizzes as it produces hydrogen gas. This reaction is not explosive but can be vigorous, making the correct choice 'It floats and fizzes, producing hydrogen gas'.

Which statement about halogens is correct?

• They form +1 ions

• Their reactivity decreases down the group

• Fluorine is the least reactive halogen

• Iodine is a gas at room temperature

Answer explanation

The correct statement is that reactivity decreases down the group. As you move from fluorine to iodine, the ability to gain electrons decreases, making the elements less reactive.

What is observed when chlorine is bubbled through potassium iodide solution?

• No reaction

• The solution turns colourless

• A brown colour appears

• A white precipitate forms

Answer explanation

When chlorine is bubbled through potassium iodide solution, it oxidizes iodide ions to iodine, resulting in a brown color due to the formation of iodine in the solution.

Which property is typical of metals?

• Brittle

• Poor electrical conductivity

• High melting points

• Dull in appearance

Answer explanation

Metals are typically characterized by high melting points due to strong metallic bonds. In contrast, they are not brittle, have good electrical conductivity, and are usually shiny, not dull.

Which of the following is a property of transition metals?

• They have low densities

• They form coloured compounds

• They are highly reactive with water

• They do not form alloys

Answer explanation

Transition metals are known for forming coloured compounds due to the presence of partially filled d-orbitals, which allow for electron transitions that absorb visible light. This property distinguishes them from many other elements.