I would like to know if this is a valid hypothesis for a Periodic Properties of the Elements lab report? The lab

I would like to know if this is a valid hypothesis for a Periodic Properties of the Elements lab report? The lab

is about examining periodic trends on a virtual periodic table.

Hypothesis: As the atomic mass increases along the periods and groups, then the density of the atom should increase as well. 

(I have to state if my hypothesis was accurate in the end of the lab report). If possible to explain if the hypothesis is accurate or not.

Thank you!