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This question is about atomic structure - AQA - GCSE Chemistry - Question 4 - 2019 - Paper 1
Question 4
This question is about atomic structure. Atoms contain subatomic particles. Table 2 shows properties of two subatomic particles. Complete Table 2. Table 2 Name ... show full transcript
Worked Solution & Example Answer:This question is about atomic structure - AQA - GCSE Chemistry - Question 4 - 2019 - Paper 1
Step 1
Complete Table 2.
Answer
To complete Table 2, we need to identify the properties of the neutron and the proton:
- For the neutron, the relative mass is 1 and the relative charge is 0 (neutral).
- The proton has a relative mass of 1 and a relative charge of +1.
| Name of particle | Relative mass | Relative charge |
|---|---|---|
| neutron | 1 | 0 |
| proton | 1 | +1 |
Step 2
Step 3
Why is the mass number different in the two isotopes?
Answer
The mass number is different in the two isotopes because they contain different numbers of neutrons while having the same number of protons. This difference in neutrons results in a variation in the overall mass number of the isotopes.
Step 4
Explain how the model of the atom changed as new evidence was discovered.
Answer
The model of the atom evolved due to findings from the alpha particle scattering experiment. Initially, the plum pudding model depicted the atom as a diffuse cloud of positive charge with electrons randomly embedded within it.
However, the scattering experiments showed that most alpha particles passed straight through the atom, indicating that the majority of the atom's mass is concentrated in a small region: the nucleus. This led to the concept that the atom has a positively charged nucleus at its center, surrounded by orbiting electrons, moving away from the earlier plum pudding interpretation.