According to the scientific method an existing theory is replaced when another theory can better account for certain experimental observations - Leaving Cert Chemistry - Question c - 2021
Question c
According to the scientific method an existing theory is replaced when another theory can better account for certain experimental observations.
John Dalton's atomic... show full transcript
Worked Solution & Example Answer:According to the scientific method an existing theory is replaced when another theory can better account for certain experimental observations - Leaving Cert Chemistry - Question c - 2021
Step 1
What was Dalton's atomic theory?
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Answer
Dalton's atomic theory states that matter is composed of atoms, which are tiny particles. Atoms are indivisible and cannot be broken down into simpler particles. Additionally, atoms cannot be created or destroyed, and all atoms of a given element are identical.
Step 2
Name the scientist whose work on cathode rays led him to identify the electron as a subatomic particle.
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Answer
The scientist is J.J. Thomson.
Step 3
What happens in a radioactive nucleus during beta decay?
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Answer
In beta decay, a neutron in the nucleus transforms into a proton while emitting an electron. The overall process can be represented as: ( n \rightarrow p + e^- ).
Step 4
What was the isotope's neutron composition?
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Answer
For the neon-20 isotope, which has 20 protons, it contains 10 neutrons in the nucleus. For neon-22, which has 22 protons, it contains 12 neutrons.
Step 5
Given the expected composition of a neon-20 atom and a neon-22 atom in terms of subatomic particles?
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For neon-20: 10 protons, 10 neutrons in the nucleus, and 10 electrons in the electron cloud. For neon-22: 12 protons, 10 neutrons in the nucleus, and 12 electrons in the electron cloud.
Step 6
Calculate the relative atomic mass of neon using Aston’s results above.
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Answer
The calculation for the relative atomic mass of neon is as follows:
Using the masses:
90.0% of neon atoms are of mass number 20 (neon-20).
The remaining 10.0% are of mass number 22 (neon-22).
