Electrons in an anion
An ion in a water treatment demonstration has atomic number \(9\) and charge \(2-\). Calculate the number of electrons. Use the diagram labels first, then answer carefully. Enter the answer and choose the interpretation that matches the chemistry.
Worked practice: chemistry evidence and answer
Use the chemical evidence first, then enter the result and interpretation that match it.
Write a full answer
Now write the response in full, in your own words — this is what the exam asks for. The AI marks it on the same moves you built above (focus, evidence, technique, judgement) and gives feedback on reasoning, evidence, and expression.