The Periodic Table
5 marks · EasyThis question is about deducing and representing electronic configurations of atoms using diagrams.
Give the electronic configuration (using numbers) for the element with atomic number 10.
Draw a diagram showing the arrangement of electrons in this atom, using shells and dots (•) for electrons.
Explain why this arrangement is stable.
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.
Show answer
(a) 2,8
(b) — · must show Two concentric shells, 2 electrons in first, 8 in second, all electrons shown as dots
(c) Both shells are full, so the atom is stable (noble gas configuration).
Common mistakes: Wrong shell order; Miscounting electrons
Show mark scheme and worked solution
Marking points
A1 (a) · 1 mark · Gives '2,8' for atomic number 10.
B1 (b) · 1 mark · Shows correct shell structure (2 shells).
B2 (b) · 1 mark · Shows correct numbers (2 in first, 8 in second shell) with dots for electrons.
E1 (c) · 1 mark · States that both shells are full (or equivalent).
E2 (c) · 1 mark · Explains that the configuration is stable because it is like a noble gas (or mentions stability due to full shells).
Worked solution
a) Atomic number 10: 2 in first shell, 8 in second shell. Configuration: 2,8.
b) Draw two circles around a center, place 2 dots in first, 8 in second shell.
c) All shells are full, making this a stable, noble gas electronic arrangement.