2H2 + 02 2H20
How does the equation above demonstrate the law of conservation of mass?

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.

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons

its first and third is your answer i did the qustion the fourth isnt right

b. is the answer hoped i