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This question is about atoms and isotopes - AQA - GCSE Chemistry - Question 4 - 2015 - Paper 2
Question 4
This question is about atoms and isotopes. Atoms contain protons, neutrons and electrons. A lithium atom has the symbol \( ^3_7Li \). Explain, in terms of sub-atomi... show full transcript
Worked Solution & Example Answer:This question is about atoms and isotopes - AQA - GCSE Chemistry - Question 4 - 2015 - Paper 2
Step 1
Explain, in terms of sub-atomic particles, why the mass number of this lithium atom is 7.
Answer
The mass number of an atom is determined by the total number of protons and neutrons present in the nucleus. For the lithium atom ( ^3_7Li ), it has 3 protons and 4 neutrons. Therefore, the mass number is calculated as follows:
Step 2
Step 3
Describe the similarities and differences between the isotopes \( ^{18}_8O \) and \( ^{16}_8O \).
Answer
The two isotopes ( ^{18}_8O ) and ( ^{16}_8O ) have similarities and differences:
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Similarities:
- Both isotopes have the same number of protons, which is 8 (this means they are both oxygen).
- They have the same number of electrons, which results in similar chemical behavior.
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Differences:
- ( ^{18}_8O ) has 10 neutrons, while ( ^{16}_8O ) has 8 neutrons, making them different isotopes of oxygen.
- The mass number of ( ^{18}_8O ) is 18, while that of ( ^{16}_8O ) is 16.