The student placed 10 ml of pbcl2 (saturated solution) in the test tube and added a pinch of lead acetate. when the test tube was shaken, a white precipitate of pbcl2 formed. as lead acetate is added, how is this affecting the quantity of pbcl2?

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.

it's c. elements are placed in rows based on how may valencies electrons have.