(a) A chlorine atom contains 17 electrons, 18 neutrons and 17 protons - Edexcel - GCSE Chemistry - Question 8 - 2018 - Paper 1
Question 8
(a) A chlorine atom contains 17 electrons, 18 neutrons and 17 protons.
(i) State the mass number of this chlorine atom.
(ii) Give the electronic configuration of t... show full transcript
Worked Solution & Example Answer:(a) A chlorine atom contains 17 electrons, 18 neutrons and 17 protons - Edexcel - GCSE Chemistry - Question 8 - 2018 - Paper 1
Step 1
(i) State the mass number of this chlorine atom.
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Answer
The mass number of an atom is calculated by adding the number of protons and neutrons. For chlorine, the mass number is:
17 (protons)+18 (neutrons)=35
Therefore, the mass number of this chlorine atom is 35.
Step 2
(ii) Give the electronic configuration of this chlorine atom.
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Answer
The electronic configuration of chlorine, which has 17 electrons, can be expressed as:
1s22s22p63s23p5
This indicates that there are 2 electrons in the first shell, 8 in the second shell, and 7 in the third shell.
Step 3
(b) Describe what you would see if damp, blue litmus paper is placed into chlorine gas.
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When damp, blue litmus paper is placed in chlorine gas, it is expected to turn red. This is because chlorine gas is acidic in nature and can produce hydrogen ions in solution, resulting in a pH lower than 7. The paper may also become white or bleached due to the bleaching property of chlorine when it reacts.
