A chlorine atom contains 17 electrons, 18 neutrons and 17 protons - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2018 - Paper 1
Question 5
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 5 - 2018 - Paper 1
Step 1
State the mass number of this chlorine atom.
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Answer
The mass number of a chlorine atom is calculated by adding the number of protons and neutrons. In this case, the chlorine atom has 17 protons and 18 neutrons:
extMassNumber=extProtons+extNeutrons=17+18=35
Thus, the mass number of this chlorine atom is 35.
Step 2
Give the electronic configuration of this chlorine atom.
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Answer
The electronic configuration of a chlorine atom, which has 17 electrons, can be written as follows:
extElectronicConfiguration=2.8.7
This indicates that there are 2 electrons in the first shell, 8 in the second shell, and 7 in the outermost shell.
Step 3
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 introduced to chlorine gas, it will turn red. Chlorine gas reacts with moisture, forming hydrochloric acid, which is acidic in nature. The acid will cause the blue litmus paper to change color to red due to the presence of hydrogen ions.
