Practice Isotope in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

Atoms of the same element that have the same number of protons but different numbers of neutrons, giving them different mass numbers.

Same element, slightly different weight. Chemically identical, but different mass.

Showing a random 20 of 50 problems.

Example 1

medium
Why is the atomic mass of an element usually not a whole number?

Example 2

medium
How many protons and neutrons in 92238U{}^{238}_{92}\text{U}?

Example 3

easy
Hydrogen has three isotopes. Name them.

Example 4

medium
Magnesium-24, Mg-25, Mg-26 differ in what?

Example 5

challenge
Why does carbon dating rely on carbon-14 decaying while carbon-12 does not, even though both are carbon?

Example 6

easy
Name a common radioisotope used in medical imaging.

Example 7

medium
Do isotopes have similar chemical behavior?

Example 8

medium
Chlorine has two stable isotopes: 35Cl{}^{35}\text{Cl} (75.78%) and 37Cl{}^{37}\text{Cl} (24.22%). Calculate the average atomic mass.

Example 9

medium
Are hydrogen-1 and hydrogen-2 (deuterium) isotopes, ions, or different elements?

Example 10

medium
Tritium is 3H{}^{3}\text{H}. How many protons, neutrons, and electrons does neutral tritium have?

Example 11

easy
Carbon-14 dating uses which isotope?

Example 12

medium
Which has more mass: a deuterium atom or a tritium atom?

Example 13

easy
Carbon has three naturally occurring isotopes: 12C{}^{12}\text{C}, 13C{}^{13}\text{C}, and 14C{}^{14}\text{C}. How many protons and neutrons does each have?

Example 14

medium
Oxygen-16 and oxygen-18 both have 8 protons. How many neutrons does each have?

Example 15

easy
True or false: 14C{}^{14}\text{C} and 14N{}^{14}\text{N} are isotopes.

Example 16

medium
Uranium-235 and uranium-238 both have Z=92Z=92. How many more neutrons does U-238 have?

Example 17

medium
Which property of an atom changes between isotopes: mass, charge, or chemical reactivity?

Example 18

medium
An element has two isotopes with masses 24 amu (78%) and 25 amu (10%) and 26 amu (12%). Calculate the average atomic mass.

Example 19

medium
Chlorine has two isotopes, Cl-35 and Cl-37. How many neutrons does each have if Z=17Z = 17?

Example 20

easy
16O{}^{16}\text{O} has 8 protons and 8 neutrons. How many neutrons does 18O{}^{18}\text{O} have?
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