A 5.0 g sample of MgCl, may contain measurable amounts of other compounds as impurities. Which of the following quantities is
(are) needed to determine that the sample is pure MgCl2 ?

(A)The color and density of the sample
(B)The mass of Mg in the sample only
(C)The number of moles of Cl in the sample only
(D)The mass of Mg and the mass of Cl in the sample

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

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.