An atom of aluminium has an atomic mass of 27 - Edexcel - GCSE Chemistry Combined Science - Question 3 - 2022 - Paper 1
Question 3
An atom of aluminium has an atomic mass of 27.
Aluminium has an atomic number of 13.
State the number of electrons, neutrons and protons in this atom.
(b) Aluminium... show full transcript
Worked Solution & Example Answer:An atom of aluminium has an atomic mass of 27 - Edexcel - GCSE Chemistry Combined Science - Question 3 - 2022 - Paper 1
Step 1
State the number of electrons:
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Answer
An aluminium atom has an atomic number of 13, which means it has 13 electrons.
Step 2
number of neutrons:
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Answer
To find the number of neutrons, subtract the atomic number from the atomic mass. Thus, the number of neutrons is: 27 (atomic mass) - 13 (atomic number) = 14.
Step 3
number of protons:
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Answer
The number of protons in an aluminium atom is equal to its atomic number, which is 13.
Step 4
Calculate the empirical formula:
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Answer
To find the empirical formula, first calculate the number of moles of each element:
Moles of Aluminium:
[
\text{Moles of Al} = \frac{1.35g}{27.0 g/mol} = 0.05
]
Moles of Bromine:
[
\text{Moles of Br} = \frac{12.00g}{80.0 g/mol} = 0.15
]
Ratio of Moles:
Divide both by the smallest value (0.05):
Aluminium: ( \frac{0.05}{0.05} = 1 )
Bromine: ( \frac{0.15}{0.05} = 3 )
Therefore, the empirical formula is ( \text{AlBr}_3 ).
