1. 750 x 10^3 ng to g

1.750×10^-6 g

Explanation:

we know n is 10^-9. all you have to do is to replace n with 10^-9.

so the answer is

1.750×10^3×10^-9 g

which is equal to 1.750×10^-6 g

if anything is unclear, ask freely.

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.