When adding the measurements 4.56 g and 0.01860 g what is the reported value (to the correct number of significant figures)?

it should be p1 v1 = p2 v2

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

14 days is the half-life of phosphorus-32