If the half-life of technitium-104 is 18.0 min, how much of a 14.2-g sample will remain after 72 minutes?
3.55g

1.78g

0.888g

0.444g

Consider the nuclear equation below. 239 > x + 4 he 94 2 what is x? 1.235 cm 96 2.243 u 92 3.235 u 92 4.243 cm 96

What happens to isotopes that are unstable?

Ican determine the molar mass of an element by looking on the under the atomic mass for the element. for example the molar mass of phosphorus is 30.974 grams/mole. avogadro’s number tells me the amount of representative particles in 1 mole of any substance. this means 12.011 gram sample of carbon and a 32.0 gram sample of sulfur have the same number of atoms.