Home / AS & A Level Chemistry 3.7 Dot-and-cross diagrams: Exam Style Questions Paper 1

AS & A Level Chemistry 3.7 Dot-and-cross diagrams: Exam Style Questions Paper 1

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A Level Chemistry Paper 1 - All Chapters

Question

Which dot-and-cross diagram is correct for \(Al_2Cl_6\)?

Answer/Explanation

Ans: B

Question

In which structure are three atoms bonded together in a straight line?
A poly(ethene), \(-(-CH_2CH_2-)_n-\)
B propane, \(C_3H_8\)
C silicon tetrachloride, \(SiCl_4\)
D sulfur hexafluoride, \(SF_6\)

Answer/Explanation

Ans: D

Question

 Which molecules contain at least one unpaired electron?

1    NO
2   NO2
3   NH3

Answer/Explanation

Answer       B

Question

The eight species that follow all have covalent bonds.

In which pair do the species have different shapes from each other?

A    BeCl2 and CO2
B    CH4 and NH4+
C    NH3 and BF3
D    SCl2 and H2O

Answer/Explanation

Answer:

C

Question

In which species is there a lone pair of electrons?
A CH3               B CH3+                  C CH3–                    D CH4

Answer/Explanation

Answer       C

Question

Which molecule contains six bonding electrons?
A \(C_2H_4\)      B \(H_2S\)      C \(NCl_3\)      D \(SF_6\)

Answer/Explanation

Ans: C

Question

Pollutant oxide Y, which contains non-metallic element X, is formed in a car engine. Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation, 1mol of Y reacts with 0.5mol of gaseous oxygen molecules. X could be either nitrogen or sulfur. Which statements about X, Y and Z can be correct?
1   The oxidation number of X increases by two from Y to Z.
2   Y has an unpaired electron in its molecule.
3  Y is a polar molecule.

The responses A to D should be selected on the basis of

Answer/Explanation

Ans:A

Question

 Use of the Data Booklet is relevant to this question.
Free-radicals play an important part in reactions involving the destruction of the ozone layer and the substitution of alkanes by chlorine.

Some free-radicals contain two unpaired electrons. Such species are called diradicals. Which species are diradicals?

1 O
2 Cl
3 \(CH_3\)

The responses A to D should be selected on the basis of

No other combination of statements is used as a correct response.

Answer/Explanation

Ans: D

Question

In which species does the underlined atom have an incomplete outer shell?
A BF3               B CH3–                C F2O                D H3O+

Answer/Explanation

Ans:

A

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