A chlorine atom contains 17 electrons, 18 neutrons and 17 protons - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2018 - Paper 1
Question 2
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 this ... show full transcript
Worked Solution & Example Answer:A chlorine atom contains 17 electrons, 18 neutrons and 17 protons - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2018 - Paper 1
Step 1
State the mass number of this chlorine atom.
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Answer
The mass number of an atom is the total number of protons and neutrons. For chlorine, it has 17 protons and 18 neutrons. Therefore, the mass number can be calculated as:
Give the electronic configuration of this chlorine atom.
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Answer
The electronic configuration for chlorine, which has 17 electrons, is:
extElectronicConfiguration=2.8.7
This indicates that there are 2 electrons in the first shell, 8 in the second shell, and 7 in the third shell.
Step 3
Describe what you would see if damp, blue litmus paper is placed into chlorine gas.
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Answer
Upon placing damp, blue litmus paper into chlorine gas, the litmus paper will first turn red. Following that, after exposure to chlorine, it may bleach and turn white. This is due to chlorine's strong oxidizing properties and its ability to react with moisture in the paper, leading to the bleaching effect.
Step 4
State why the litmus paper turns red.
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Answer
The litmus paper turns red because when hydrogen chloride (HCl) dissolves in water, it produces hydrochloric acid, which is acidic in nature. The acid releases hydrogen ions (H⁺) in solution, causing the blue litmus paper to change color to red.
