What is a disadvantage of using a space-filling model to show a chemical compound?

First you have to know what the space-filling model is. The space-filling model is a model used to show the structure of the atoms. It specially shows the relative sizes of the atoms and how the space between atoms (inside the molecule) is filled. It does not show the angles and lengths of the bonds. So, the disadvantage of using a space-filling model to show a chemical compound is that it will not permit to observe neither the angles nor the lengths of the bonds in the molecule.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer