CIE Chemistry Paper-1: Specimen Questions 68 - 69 of 99

Question number: 68

MCQ▾

Question

Which of the following describes the correct Lewis dot structure for magnesium chloride.

Choices

Choice (4) Response
a.
Finding correct Lewis Dot Structure – Choice A

Finding correct Lewis Dot Structure – Choice A

Which is the correct Lewis Dot Structure

b.
Finding correct Lewis Dot Structure – Choice B

Finding correct Lewis Dot Structure – Choice B

Which is the correct Lewis Dot Structure

c.
Finding correct Lewis Dot Structure – Choice C

Finding correct Lewis Dot Structure – Choice C

Which is the correct Lewis Dot Structure

d. None of the above

Answer

b.

Explanation

Magnesium whose atomic number is 12, has 2, 8, 2 configuration. So, it has two electrons in its valence shell. The electronic configuration of chlorine (At. no. 17) is 2, 8, 7. So it has seven valence electrons. Since, magnesium has two electrons in excess of the neon configuration

(2, 8), and chlorine is one electron short of the argon configuration (2, 8, 8), hence one atom of magnesium will transfer its two electrons to two atoms of chlorine (one to each) as shown below:

Order of Lewis Dot Structure

Order of Lewis Dot Structure

Formation of Lewis Dot Structure

Question number: 69

MCQ▾

Question

An oxidation reaction takes place when copper powder kept in a china plate is heated. A black coating is formed on the surface of copper. What product is formed in the above reaction?

shows Oxidation of copper

shows Oxidation of copper

Understanding the process of oxidation of copper

Choices

Choice (4) Response
a.

Copper oxide

b.

Copper Nitrate

c.

Copper sulphate

d. All of the above

Answer

a.

Explanation

Following reaction will take place when copper will be heated.

2Cu + O₂ 2CuO

Therefore copper oxide is formed.

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