What are the similarities and differences between polyatomic ions and monoatomic ions?

When would a bouncy ball have the most potential energy

0.09 moles of sodium sulfate in 12 ml of solution

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?