An oxygen atom has six outer-shell electrons. A hydrogen atom has one electron.
A student's diagram of water contains two shared pairs but no other electrons.
Draw a complete outer-shell dot-and-cross diagram of water. Use dots for oxygen's electrons and crosses for hydrogen's electrons.
Explain what is missing from the student's diagram and why those electrons should not be placed on the hydrogen atoms.
State how many electrons are shown in total in your completed outer-shell diagram and explain how this total is obtained from the separate atoms.
53 exam-style questions on Edexcel GCSE Chemistry 2.4 Covalent bonding, covering 2.4.1 Covalent bonding and simple molecules. Each one has a worked solution and a mark scheme showing where the marks go.