Answer:
where is the model? i can not awser your question without it.
Ok, so... 20.219 grams is the mass of the flask with the water in it.
10.267 grams is the mass of only the flask. Subtract them to find the water mass.
20.219 g (flask+water) - 10.267 g (flask) = 9.952 g (water)
Each element shows the group and period they are through the number of energy level and valence electron in which can determine their place in the periodic table.