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Tag Archives: Ions

Elements Compounds, Mixtures, Atoms, Molecules

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I compiled some questions from assessment books and a few good schools in Singapore.

Here are some of “warm-up” questions on this topic.

As usual, those students who receive my mobile msg to attempt this week’s questions,

here you go! 🙂


1) A student wrote “Bronze is a compound.”

Explain why this statement is incorrect. [Anglo-Chinese School]

2)Iron sulphide is formed from iron and sulphur. Which of the following statements about iron sulphide is true? [Anglo-Chinese School]

A)Heat energy is required to cause the formation of iron sulphide

B)Iron sulphide has similar properties as iron

C)Iron sulphide is the result of a change in state of iron and sulphur

D)The ratio of iron to sulphur is not fixed in a sample of iron sulphide.

3) Which 2 of the following boxes consist of only 1 element?

[St Margaret Secondary School]

A)I and II

B)I and III

C)II and III

D)II and IV

4) Which of the following has the same number of atoms as Ca(OH)2?

[St Margaret Secondary School]





5) Given that the electronic configuration of nitrogen atom is 2,5.

Which of the following statements is true for the ion of nitrogen?

[St Margaret Secondary School]

Number   of Protons Number   of electrons
A 7 7
B 7 10
C 10 7
D 10 10

6) How many different elements are there in ammonium carbonate (NH4)2CO3? [Temasek Secondary School]





7) [Preston Assessment book]

a)  Classify the following substances into elements, mixtures and compounds: ice, brass, silicon, salt, ink, starch solution, plastic, potassium, protein, glass, carbon, air.

b) Explain why sugar solution is a mixture while sugar is a compound.

8)Please write the formula and names of elements of the compound below. [Anglo-Chinese School]

Compound Formula   of compound Names   of elements found in compound
Nitric   acid
Common   Salt