What is the understand portion of the mushroom called

This is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table.

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?

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5