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This question is about atoms, molecules and nanoparticles - AQA - GCSE Chemistry - Question 3 - 2016 - Paper 2
Question 3
This question is about atoms, molecules and nanoparticles. 3 (a) Different atoms have different numbers of sub-atomic particles. 3 (a) (i) An oxygen atom can be re... show full transcript
Worked Solution & Example Answer:This question is about atoms, molecules and nanoparticles - AQA - GCSE Chemistry - Question 3 - 2016 - Paper 2
Step 1
Step 2
Explain why $$^{12}_{6}C$$ and $$^{14}_{6}C$$ are isotopes of carbon.
Answer
and are isotopes of carbon because they have the same number of protons (6) in their nucleus but different numbers of neutrons. Specifically, has 6 neutrons, while has 8 neutrons. This difference in neutron number leads to different mass numbers, categorizing them as isotopes.
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), the oxygen atom has 6 outer shell electrons, while each hydrogen atom has 1 outer shell electron. To represent this, we place the oxygen atom in the center with lines or dots showing bonding pairs connecting to the hydrogen atoms:
H •
| \
•O•
|
H •
Each line represents a covalent bond formed by sharing electrons.
Step 4
Step 5
Step 6
How does the size of a nanoparticle compare with the size of an atom?
Answer
Nanoparticles are generally larger than individual atoms. While atoms are on the scale of a few angstroms (10⁻¹⁰ meters), nanoparticles can range from several nanometers (10⁻⁹ meters) to hundreds of atoms in size, making them significantly larger.
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 cobalt oxide nanoparticles have a larger surface area compared to cobalt oxide powder. This increased surface area allows for more active sites for reactions to occur, enhancing catalytic activity.