Atomic StructureEdexcel GCSE Chemistry: Topic test

20 questions, 54 marks

Edexcel GCSE Chemistry

Atomic Structure topic test

Total 54 marks

Name

Class

Date

1
A student is given information cards for three subatomic particles found in atoms: protons, neutrons and electrons, and is asked to compare their relative charges and relative masses before building a simple particle diagram of a nitrogen atom, which has atomic number 7 and mass number 14.
(a)
Which row correctly gives the relative charge and relative mass of a proton and of an electron?
[1 mark]
AProton: charge +1, relative mass 1; Electron: charge -1, relative mass negligible
BProton: charge -1, relative mass 1; Electron: charge +1, relative mass negligible
CProton: charge +1, relative mass negligible; Electron: charge -1, relative mass 1
DProton: charge +1, relative mass 1; Electron: charge +1, relative mass negligible
(b)
The nitrogen atom shown on the card has atomic number 7 and mass number 14. How many neutrons does this atom contain?
[1 mark]
A14
B7
C21
D6
(c)
Explain why atoms contain equal numbers of protons and electrons, and state the number of electrons in this nitrogen atom.
[2 marks]
Total for question 1: 4 marks
2
A chemistry teacher shows the class the electronic configurations of three elements written as 2.3, 2.8.4 and 2.8.6, and asks the class to work out where each element must be found in the periodic table.
(a)
An element has the electronic configuration 2.8.4. Which group of the periodic table is it in, and why?
[1 mark]
AGroup 8, because it has a total of 8 electrons in its first two shells
BGroup 3, because its electrons occupy three shells
CGroup 4, because it has 4 electrons in its outer shell
DGroup 6, because 2 more electrons would fill its outer shell to make 6
(b)
An element has the electronic configuration 2.8.6. Which period of the periodic table is it in, and why?
[1 mark]
APeriod 6, because its outer shell holds 6 electrons
BPeriod 2, because its second shell holds the most electrons
CPeriod 8, because its second shell holds 8 electrons
DPeriod 3, because its electrons occupy three shells
(c)
Explain how the electronic configuration of an element is related to its position in the periodic table, using the element with configuration 2.3 as an example to state its group and period.
[2 marks]
Total for question 2: 4 marks
3
A student investigates the compound magnesium chloride, formed when magnesium reacts with chlorine. A magnesium atom has the electronic configuration 2.8.2, and a chlorine atom has the electronic configuration 2.8.7.
(a)
Describe, in terms of electron transfer, how the ions in magnesium chloride are formed from magnesium and chlorine atoms, and state the charges on the resulting ions.
[3 marks]
(b)
Deduce the formula of magnesium chloride from the charges on its ions, and describe the structure of the solid compound formed, including the type of force holding the ions together.
[4 marks]
Total for question 3: 7 marks
4
A materials scientist compares two substances used in the electronics industry: silicon dioxide, a giant covalent substance, and iodine, a simple molecular covalent substance, and wants to explain why they behave so differently when heated and when tested for electrical conductivity.
(a)
Explain, in terms of bonding and structure, why silicon dioxide has a very high melting point while iodine has a low melting point.
[6 marks]
(b)
The scientist also tests molten silicon dioxide and molten magnesium chloride (an ionic compound) for electrical conductivity. Explain why molten silicon dioxide does not conduct electricity, whereas molten magnesium chloride does, referring to the particles present in each case.
[6 marks]
Total for question 4: 12 marks
5
A student heats 2.4 g of magnesium ribbon in a crucible until it has fully reacted with the oxygen in the air, forming magnesium oxide. (Relative atomic masses: Mg = 24, O = 16)
(a)
What is the relative formula mass of magnesium oxide, MgO?
[1 mark]
A24, using only the relative atomic mass of magnesium
B40, the sum of the relative atomic masses of magnesium and oxygen
C16, using only the relative atomic mass of oxygen
D64, doubling the relative atomic mass of magnesium
(b)
What is the percentage by mass of magnesium in magnesium oxide, MgO?
[1 mark]
A40%, the percentage of oxygen by mass
B16%, using oxygen's relative atomic mass as a percentage
C60%, calculated as (24 / 40) x 100
D96%, calculated as 24 x 4
(c)
Calculate the mass of oxygen that reacted with the 2.4 g of magnesium, given that magnesium oxide has the formula MgO.
[2 marks]
Total for question 5: 4 marks
6
A student is asked to deduce the formula of potassium oxide, formed from potassium ions and oxide ions, given that a potassium atom has the electronic configuration 2.8.8.1 and an oxygen atom has the electronic configuration 2.6.
(a)
An oxygen atom gains electrons to achieve a stable, full outer shell, forming an oxide ion. What is the charge on the resulting oxide ion, and how many electrons does the atom gain?
[1 mark]
A2+ charge, loses 2 electrons
B1- charge, gains 1 electron
C6- charge, gains 6 electrons
D2- charge, gains 2 electrons
(b)
Using the charges on potassium ions (1+) and oxide ions (2-), what is the formula of potassium oxide?
[1 mark]
AK2O, since two 1+ potassium ions balance one 2- oxide ion
BKO2, with the subscripts the wrong way round
CKO, assuming a 1:1 ratio without balancing charge
DK2O2, adding the charges together instead of balancing them
(c)
Explain, in terms of electron transfer, how a potassium ion is formed from a potassium atom, given that a potassium atom has the electronic configuration 2.8.8.1.
[2 marks]
Total for question 6: 4 marks
7
A technician is given three elements, silicon (atomic number 14), phosphorus (atomic number 15) and sulfur (atomic number 16), and is asked to identify each as a metal or non-metal from its position in the periodic table, then work out their electronic configurations.
(a)
State whether silicon, phosphorus and sulfur are metals or non-metals, and explain how their position in the periodic table shows this.
[3 marks]
(b)
Predict the electronic configurations of silicon, phosphorus and sulfur, and explain how these configurations relate to their group and period in the periodic table.
[4 marks]
Total for question 7: 7 marks
8
Copper exists naturally as two isotopes: copper-63, which makes up 69% of copper atoms, and copper-65, which makes up the remaining 31%. A technician reacts a 6.35 g sample of copper with excess sulfur to produce copper(II) sulfide, CuS. (Relative atomic masses: Cu = 63.5, S = 32)
(a)
Calculate the relative atomic mass of copper from this isotope data, giving your answer to one decimal place, and explain why the relative atomic masses of some elements are not whole numbers.
[6 marks]
(b)
Using a relative atomic mass of 63.5 for copper, calculate the number of moles of copper in the 6.35 g sample, the mass of sulfur needed to react completely with it to form copper(II) sulfide, CuS, and hence the total mass of copper(II) sulfide produced. Show your working.
[6 marks]
Total for question 8: 12 marks

End of questions