What terms are used to indicate the maximum distance

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?

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

How many molecules are in 6.0 moles of methane