Because size of an atom INCREASES from top to bottom and DECREASES from left to right on the periodic table. If to elements are in the same period they can't increase in size based on the up or down trend. Instead, notice that Alkali Metals are LEFT of Alkaline Earth Metals. Therefore, the Alkali Metal will be larger than the Alkaline Earth Metals.
Second choice is electron cloud and first is a discrete amount thst is fixed
Answer:
Spectral patterns are unique to each element so they are used to identify the metal ions in the salts used in the flame tests.
