The arrangement of the electrons in an atom
2 marks · HardElement Z is found in Group 5 and Period 3 of the Periodic Table.
Explain what the group and period numbers tell you about the arrangement of electrons in an atom of element Z.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Must show: Group number: 5 electrons in outer shell, Period number: 3 shells/energy levels
Also accept: Group number = number of electrons in the outer shell; period number = number of shells.; Group gives outer electrons; period gives number of shells present.
Common mistakes: Confusing group with period.; Saying group is number of shells.
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Marking points
B1 · 1 mark · States or explains that the group number (5) shows number of electrons in the outer shell (energy level).
B2 · 1 mark · States or explains that the period number (3) shows the atom has three shells (energy levels).
Worked solution
The group number (5) tells us there are 5 electrons in the outer shell of element Z.
The period number (3) means there are 3 energy levels (shells) in the atom.