Isotopes Practice Quiz
5 Questions
| Attempts: 3772
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How does it change?
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They're not there anymore.
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They move to a different place.
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There are different numbers of them.
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About This Quiz
A 5-question practice quiz for the topic on Isotopes at www. Thechemwhiz. Piczo. Com
Note: you'll need a calculator.
Quiz Preview
- 2.
Magnesium has three of it's own isotopes. 78.7% is Magnesium-24. 10.13% is Magnesium-25. 11.17% is Magnesium-26. Calculate the relative atomic mass of Magnesium, to two decimal places.
Explanation
(78.7 x 24) + (10.13 x 25) + (11.17 x 26)
/100
= 24.32Rate this question:
- 3.
Calculator time! 19.9% of all Boron atoms are Boron-10. 80.1% are Boron-11. Calculate the approximated relative atomic mass of Boron, to one decimal place.
Explanation
(19.9 x 10) + (80.1 x 11)
/100
= 10.8Rate this question:
- 4.
In an isotope, which part of the atom changes?
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Protons
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Neutrons
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Electrons
Correct Answer
A. Neutrons -
- 5.
Element A occurs naturally in the environment. Scientists have found 612 atoms of A-15, 829 atoms of A-16, and 244 atoms of A-17. Calculate the relative atomic mass of the element A to two decimal places.
Correct Answer
15.78Explanation
First, you have to get the percentages of all these isotopes of Element A. Add them all up together.
612+829+244 = 1685
Then, find the percentages of each - use the formula ([Number of Atoms/Total in the Sample] x 100)
([612/1685] x 100) = 36.32% of A-15.
([829/1685] x 100) = 49.20% of A-16
([244/1685] x 100) = 14.48% of A-17.
Now do what you've always done - multiply the percentages by the masses, add them all up, and divide by 100.
(36.32 x 15) + (49.20 x 16) + (14.48 x 17)
/100
= 15.78Rate this question:
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Current Version
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Mar 21, 2022Quiz Edited by
ProProfs Editorial Team -
Nov 06, 2011Quiz Created by
Superoxideion01
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