Structural isomerism in the alkanes
2 marks · HardExplain why it is not possible to have a structural isomer of methane (CH4).
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
Methane contains only one carbon atom, so there is only one way to arrange its atoms. Therefore, it cannot have any structural isomers.
Also accept: With only one carbon atom, there are no different possible structures.; There is only one possible structure for methane.
Common mistakes: Confusing structural isomers with isotopes.; Claiming that hydrogen atoms can be arranged differently.; Mentioning different positions for hydrogens, which is not possible for methane.
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that methane only has one carbon atom.
B2 · 1 mark · Explains there is only one way to connect the atoms, so no structural isomers are possible.
Worked solution
Methane (CH4) has only one carbon atom. There is only one possible way to connect one carbon atom with four hydrogen atoms, so no structural isomers are possible.