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3 (a) Two isotopes of uranium are U-235 and U-238 - Edexcel - GCSE Physics - Question 3 - 2012 - Paper 1
Question 3
3 (a) Two isotopes of uranium are U-235 and U-238. Here are the symbols of the nuclei of these isotopes. 235 92 U and 238 92 U (i) Complete the sentence by puttin... show full transcript
Worked Solution & Example Answer:3 (a) Two isotopes of uranium are U-235 and U-238 - Edexcel - GCSE Physics - Question 3 - 2012 - Paper 1
Step 1
Complete the sentence by putting a cross (✗) in the box next to your answer. The U-235 isotope has
Answer
The U-235 isotope has C more neutrons than U-238.
Explanation:
- U-238 has 146 neutrons (238 - 92).
- U-235 has 143 neutrons (235 - 92).
- Thus, U-235 has fewer neutrons, making option C correct.
Step 2
Describe an alpha particle.
Answer
An alpha particle consists of 2 protons and 2 neutrons, making it identical to a helium nucleus. It is positively charged and relatively heavy compared to other forms of radiation. When emitted from a radioactive substance, an alpha particle carries kinetic energy and can travel short distances in air. Alpha particles are unable to penetrate materials effectively, often being stopped by a sheet of paper or the outer layer of human skin.