Elements NDA Questions

NDA Chemistry

Elements MCQ Questions


7.
Which of the following statements about pure substances is true?
i.They can only be elements
ii. They can only be compounds
iii.They can be elements or compounds
iv.They can be mixtures
A.
i and ii only
B.
ii only
C.
iii only
D.
All the above
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ANSWER :
C. iii only
8.
What is the composition of a pure substance?
A.
Heterogeneous
B.
Homogeneous
C.
Both heterogeneous and homogeneous
D.
Neither heterogeneous nor homogeneous
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ANSWER :
B. Homogeneous
9.
What term describes the regular recurrence of certain atomic properties?
A.
Periodicity
B.
Cyclicity
C.
Uniformity
D.
Repetitiveness
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ANSWER :
A. Periodicity
10.
What is the most abundant type of atom in the universe?
A.
Oxygen
B.
Hydrogen
C.
Iron
D.
Silicon
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ANSWER :
B. Hydrogen
11.
Approximately what percentage of atoms in the universe are hydrogen atoms?
A.
50%
B.
60%
C.
74%
D.
90%
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ANSWER :
C. 74%
12.
What do we call properties that repeat themselves after regular intervals?
A.
Irregular properties
B.
Periodic properties
C.
Random properties
D.
Chaotic properties
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ANSWER :
B. Periodic properties