An unknown piece of metal absorbs 1350 J of heat as 55.0 g of the metal heats up from 20.0 oC to 47.0 oC

Tin has ten stable isotopes. the heaviest, 124sn, makes up 5.80% of naturally occuring tin atoms. how many atoms of 124sn are present in 82.0 g of naturally occurring tin? what is the total mass of the 124sn atoms in this sample?

Which element is least likely to undergo a chemical reaction

Why do electrons further from the nucleus have more energy