The bond length of the C-Cl bond is that of the C-H bond.
A
B
С
shorter
than
longer
than
the same
as

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

that's what i got you can count the number of atoms