Atomic Structure, Isotopes and Relative Atomic Mass - Worksheets, Questions and Revision

15 original exam-style questions - 4 pages of questions with a full mark scheme - free printable PDF.

Download PDF Jump to mark scheme (page 5)Atomic Structure, Isotopes and Relative Atomic Mass revision guide

This topic is chapter 2 of IGCSE Chemistry Practice Book.

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2.2 Atomic Structure, Isotopes and Relative Atomic Mass

EDEXCEL 4CH1 · Calculator allowed · about 45 minutes

Total Marks

Name: _______________________________ Date: ____ / ____ / ______

Answer ALL questions. Show all your working.

State the charge of a proton, as used when describing atomic structure in chemistry.

(Total for Question 1 is 1 mark)

State the relative mass of a neutron compared with the mass of a proton, as taught in atomic structure.

(Total for Question 2 is 1 mark)

State the charge of an electron, as used in descriptions of atomic particles.

(Total for Question 3 is 1 mark)

Complete the electronic configuration for calcium, element number 20, using shell notation 2,8,8 etc, as in classroom practice.

(Total for Question 4 is 1 mark)

A teacher writes the nuclide notation 56 26 Fe on the whiteboard. State the atomic number and the mass number for this iron nuclide, as a short notation exercise.

(Total for Question 5 is 2 marks)

Complete the definition used in chemistry lesson notes: An isotope of an element is an atom that has the same number of protons but a different number of what? Provide the missing word.

(Total for Question 6 is 2 marks)

Complete the electronic structure for chlorine, element number 17, as used when practising shell notation for the first 20 elements. Write the filled shells as numbers separated by commas.

(Total for Question 7 is 1 mark)

An exam-style question gives the electron configuration 2,8,1 for an element in the first 20. Deduce how many electron shells this atom has and how many electrons are in its outer shell.

(Total for Question 8 is 1 mark)

The nuclide 27 13 Al is used in a lesson exercise. State the number of electrons in the outer shell of a neutral aluminium atom, and give its electronic configuration in shell notation.

(Total for Question 9 is 2 marks)

A chemist writes the nuclide symbol 23 11 Na when discussing the element sodium in a sample. From this nuclide symbol, deduce the number of protons, neutrons and electrons in a neutral atom of this sodium isotope.

(Total for Question 10 is 3 marks)

A sample contains the radioactive nuclide carbon-14, written 14 6 C when describing its nucleus. Using this nuclide symbol, deduce the numbers of protons, neutrons and electrons in a neutral carbon-14 atom.

(Total for Question 11 is 3 marks)

Calculate the number of neutrons in a neutral atom of lead-208, written 208 82 Pb, which students often need to find when practising nuclide arithmetic.

(Total for Question 12 is 2 marks)

Calculate the relative atomic mass (Ar) of chlorine in a sample where 75% of the atoms are chlorine-35 and 25% are chlorine-37, a question a teacher might set for practice with weighted means.

(Total for Question 13 is 3 marks)

A classroom question asks for the relative atomic mass of element X which has three isotopes: X-10 with 20% abundance, X-11 with 70% abundance and X-12 with 10% abundance. Calculate the Ar of X, showing the equation, substitution and final value.

(Total for Question 14 is 4 marks)

A chemistry worksheet gives copper isotopic abundances: copper-63 is 69.2% and copper-65 is 30.8%. Calculate the relative atomic mass (Ar) of copper from these abundances, showing the equation, substitution and final value.

(Total for Question 15 is 3 marks)

Mark scheme · 2.2 Atomic Structure, Isotopes and Relative Atomic Mass

Question 1

B1 positive (+1) charge
Answer: +1 (positive)

Question 2

B1 about 1 (same as a proton) or 1 relative mass unit
Answer: Approximately 1 (the neutron has about the same mass as a proton)

Question 3

B1 negative (-1) charge
Answer: -1 (negative)

Question 4

B1 2,8,8,2
Answer: 2,8,8,2

Question 5

B1 atomic number = 26
B1 mass number = 56
Answer: Atomic number 26; Mass number 56

Question 6

B1 neutrons
B1 accept 'neutron number' or 'number of neutrons'
Answer: neutrons

Question 7

B1 2,8,7
Answer: 2,8,7

Question 8

B1 3 shells
Answer: Three shells; outer shell has 1 electron

Question 9

B1 outer electrons = 3
B1 configuration = 2,8,3
Answer: Outer electrons 3; configuration 2,8,3

Question 10

B1 protons = 11 (atomic number 11)
B1 neutrons = 23 - 11 = 12
B1 electrons = 11 (neutral atom has equal protons and electrons)
Answer: Protons 11; Neutrons 12; Electrons 11

Question 11

B1 protons = 6
B1 neutrons = 14 - 6 = 8
B1 electrons = 6 (neutral atom)
Answer: Protons 6; Neutrons 8; Electrons 6

Question 12

M1 uses neutrons = mass number - atomic number = 208 - 82
A1 neutrons = 126 cao
Answer: 126

Question 13

M1 writes Ar = (35 x 75/100) + (37 x 25/100) or equivalent weighted mean expression
M1 substitutes values and performs multiplication correctly: 35 x 0.75 = 26.25 and 37 x 0.25 = 9.25
A1 Ar = 35.5 cao
Answer: 35.5

Question 14

M1 writes Ar = (10 x 0.20) + (11 x 0.70) + (12 x 0.10) or equivalent weighted mean
M1 performs the multiplications correctly: 10 x 0.20 = 2.0, 11 x 0.70 = 7.7, 12 x 0.10 = 1.2
M1 adds the contributions correctly: 2.0 + 7.7 + 1.2
A1 Ar = 10.9 cao
Answer: 10.9

Question 15

M1 writes Ar = (63 x 0.692) + (65 x 0.308) or equivalent
M1 performs the multiplications correctly: 63 x 0.692 = 43.596 and 65 x 0.308 = 20.02 (allow awrt)
A1 Ar = 63.616 cao, accept 63.62 to 2 dp
Answer: 63.616 (awrt 63.62)

Atomic Structure, Isotopes and Relative Atomic Mass - Worksheets, Questions and Revision

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2.2 Atomic Structure, Isotopes and Relative Atomic Mass

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