2020 P1 Q3 - Determine Charge from Proton, Neutron and Electron Number

Let Chemistry Guru, Singapore's renowned JC Chemistry tuition centre, guide you through 2020 A Levels H2 Chemistry Paper 1 Question 3.

We are required to determine this unknown ion by deducing the proton, neutron and electron number.

We know that atomic or proton number is from 84 to 87. Let's find out what these elements are.

Now we can figure out the proton number, neutron number, electron number and charge of each element:
- proton number is the same as atomic number
- neutron number is nucleon number 217 minus proton number
- electron number is neutron number minus 50
- charge of ion is proton number less electron number

From the calculations we will have the following ions: Po⁺, At³⁺, Rn⁵⁺, Fr⁷⁺.

We can now compare with the options and see which is consistent.

Option B with At³⁺ should be the correct answer.

Topic: Atomic Structure, Physical Chemistry, A Level Chemistry, Singapore

Back to list of questions for 2020 A Level H2 Chemistry Paper 1.

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