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Different atoms have different numbers of sub-atomic particles - AQA - GCSE Chemistry - Question 3 - 2016 - Paper 2
Question 3
Different atoms have different numbers of sub-atomic particles. 3 (a) (i) An oxygen atom can be represented as \(^{16}_{8}O\). Explain why the mass number of this ... show full transcript
Worked Solution & Example Answer:Different atoms have different numbers of sub-atomic particles - AQA - GCSE Chemistry - Question 3 - 2016 - Paper 2
Step 1
Explain why the mass number of this atom is 16.
Answer
The mass number of an atom is the total number of sub-atomic particles in its nucleus, which includes both protons and neutrons. In the case of the oxygen atom represented as (^{16}_{8}O), it has 8 protons and 8 neutrons, giving a mass number of 16 (8 + 8 = 16).
Step 2
Explain why \(^{12}_{6}C\) and \(^{14}_{6}C\) are isotopes of carbon.
Answer
Both (^{12}{6}C) and (^{14}{6}C) have the same number of protons, which is 6, making them carbon isotopes. The difference lies in the number of neutrons: (^{12}{6}C) has 6 neutrons, while (^{14}{6}C) has 8 neutrons.
Step 3
Complete Figure 3 to show the arrangement of the outer shell electrons of the hydrogen and oxygen atoms in a molecule of water.
Answer
In a water molecule (H₂O), there are two hydrogen atoms (H) and one oxygen atom (O). The oxygen atom has 6 outer shell electrons and will form 2 bonding pairs with the two hydrogen atoms, each sharing one electron. The diagram would show dots or crosses representing the respective electrons around each atom.
Step 4
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Step 6
How does the size of a nanoparticle compare with the size of an atom?
Answer
Nanoparticles are larger than atoms. While atoms generally consist of a few hundred picometers in size, nanoparticles typically range from a few nanometers to hundreds of nanometers, accommodating the size of several hundred atoms.
Step 7
Suggest one reason why 1 g of cobalt oxide nanoparticles is a better catalyst than 1 g of cobalt oxide powder.
Answer
One reason is that 1 g of cobalt oxide nanoparticles has a much larger surface area compared to 1 g of cobalt oxide powder. This increased surface area allows for more active sites for catalytic reactions, enhancing the efficiency of the catalyst.