8. Which of the following comparisons about main group metals and transition metals is INCORRECT?

Main group metals

A. They have lower melting points.

B. Their ions in aqueous solution are usually colourless.

C. They usually form only one type of simple ion.

D. They are generally not used as catalysts.

Part B - Assertion-reason question

Transition metals

They have higher melting points.

All transition metal ions in aqueous solution are coloured.

They can form two or more simple cations with different charges.

They are usually used as catalysts.

A B C D

9. 10.

Both statements are true and the 2nd statement is a correct explanation of the 1st statement. Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement. The 1st statement is false but the 2nd statement is true.

Both statements are false.

The melting point of elements decreases across a period.

Amphoteric oxides react with both acids and alkalis.

Across a period, elements change from metals, through semi-metals to non-metals. Amphoteric oxides show both alkaline and acidic properties.