Application Questions - Atomic Structure

Chemistry: AQA GCSE Higher, topic 1.1.31

Test yourself on Application Questions - Atomic Structure

An imaginary element, Y, has two different isotopes.
²⁵Y has a percentage abundance of 25% and ²⁹Y has a percentage abundance of 75%.

Which of the following is the relative atomic mass of Y?
Sodium contains 11 electrons. What is the electronic structure of sodium?
Calcium carbonate reacts with hydrochloric acid to form calcium chloride, carbon dioxide, and water. Which of the following is a balanced equation for this reaction?