Which pair are isotopes?

Question

Which pair are isotopes??  
A. Co 60 and Kr 70  
B. K 40 and Ar 40  
C. O 15 and O 18  
D. N 14 and C 14

Accepted Answer

Correct Answer: (C)O 15 and O 18. 
Rationale: Oxygen-15 and oxygen-18 are isotopes.Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. Because the element is defined by its proton number (atomic number), isotopes must belong to the same element while differing in mass number.A. Co-60 and Kr-70Cobalt-60 and krypton-70 are different elements with different atomic numbers. Since isotopes must be atoms of the same element, this pair cannot be isotopes.B. K-40 and Ar-40Although potassium-40 and argon-40 share the same mass number, they are different elements with different atomic numbers. They are related through radioactive decay, but they are not isotopes of each other.C. O-15 and O-18Both atoms are oxygen, which means they each have 8 protons. Oxygen-15 has 7 neutrons, while oxygen-18 has 10 neutrons. The difference in neutron number gives them different mass numbers while remaining the same element.D. N-14 and C-14Nitrogen-14 and carbon-14 have the same mass number but different atomic numbers. Such atoms are called isobars, not isotopes.ConclusionIsotopes must be atoms of the same element with different mass numbers. Oxygen-15 and oxygen-18 meet this requirement, making option C the correct choice.

Which pair are isotopes?

A
Co 60 and Kr 70

B
K 40 and Ar 40

C
O 15 and O 18

D
N 14 and C 14

Oxygen-15 and oxygen-18 are isotopes.

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Related Questions

Which pair are isotopes?

A Co 60 and Kr 70 B K 40 and Ar 40 C O 15 and O 18 D N 14 and C 14

Oxygen-15 and oxygen-18 are isotopes.

Topic Flashcards

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Related Questions

A
Co 60 and Kr 70

B
K 40 and Ar 40

C
O 15 and O 18

D
N 14 and C 14