Relative atomic mass from isotope abundances
10th grade (Year 11 in England) · 16 questions · Common Core: NGSS.HS-PS1-1, NGSS.SEP 5 · England: GCSE Combined Science: Atomic structure (relative atomic mass)
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Question 1
An element has two isotopes: mass 38 (90 %) and mass 40 (10 %). What is its relative atomic mass? Give 1 decimal place.
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Question 2
Natural magnesium contains 79 % of mass 24 and 10 % of mass 25 and 11 % of mass 26. Calculate its relative atomic mass to 1 decimal place.
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Question 3
What are isotopes?
- A. ions with different charges
- B. atoms of the same element with different numbers of neutrons
- C. atoms of different elements with the same mass
- D. atoms with different numbers of protons
Question 4
An element has two isotopes: mass 49 (10 %) and mass 51 (90 %). What is its relative atomic mass? Give 1 decimal place.
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Question 5
Natural copper contains 69 % of mass 63 and 31 % of mass 65. Calculate its relative atomic mass to 1 decimal place.
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Question 6
Carbon-12 and carbon-14 are isotopes. How many neutrons does carbon-14 have? (Carbon has 6 protons.)
- A. 12
- B. 6
- C. 8
- D. 14
Question 7
An element has two isotopes: mass 63 (70 %) and mass 65 (30 %). What is its relative atomic mass? Give 1 decimal place.
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Question 8
Natural copper contains 69 % of mass 63 and 31 % of mass 65. Calculate its relative atomic mass to 1 decimal place.
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Question 9
Do isotopes of the same element react differently in chemical reactions?
- A. Yes: they have different numbers of protons
- B. Yes: heavier isotopes are always more reactive
- C. No: they have the same electron arrangement, so their chemistry is the same
- D. No: isotopes never react
Question 10
An element has two isotopes: mass 61 (20 %) and mass 63 (80 %). What is its relative atomic mass? Give 1 decimal place.
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Question 11
Natural boron contains 20 % of mass 10 and 80 % of mass 11. Calculate its relative atomic mass to 1 decimal place.
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Question 12
What are isotopes?
- A. atoms of the same element with different numbers of neutrons
- B. atoms with different numbers of protons
- C. ions with different charges
- D. atoms of different elements with the same mass
Question 13
An element has two isotopes: mass 29 (70 %) and mass 31 (30 %). What is its relative atomic mass? Give 1 decimal place.
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Question 14
Natural gallium contains 60 % of mass 69 and 40 % of mass 71. Calculate its relative atomic mass to 1 decimal place.
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Question 15
Why is the relative atomic mass of chlorine 35.5 and not a whole number?
- A. Chlorine atoms have half a neutron
- B. It is an average of its isotopes, weighted by abundance
- C. It is measured badly
- D. Electrons add 0.5
Question 16
An element has two isotopes: mass 50 (20 %) and mass 52 (80 %). What is its relative atomic mass? Give 1 decimal place.
Answer
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