Which conversion factor do you use first to caluclate the number of grams of FeCl3 produced by the reaction of 30.3 grams of iron reacting with chlorine.
2 Fe + 3 Cl2 + 2 FeCl3

tracks, burrows, eggshells, nests, tooth marks, or gastroliths

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.