describe what the periods and groups on the periodic table are, how they are different, and what they tell us about an atoms structure.

What is the mass of phosphorous in a 51-kg person

Calculate the mass of 0.750 mol of the following substance. na3po4.

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.