Thorium-229 is a highly radioactive isotope used in the treatment of certain cancers. use the chart to determine how much thorium would remain after 7,340 years if a sample began at 20 pounds of pure th-229.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

1kg of water needs to recieve 4200j of energy to go from 90 degrees to 91 degrees. what is the specific heat capacity of water? what are the units?

On your wedding day your lover gives you a gold ring of mass 3.67 g. 48 years later its mass is 3.44 g. on the average how many atoms were abrated from the ring during each second of your marriage? the atomic mass of gold is 197 u. don't enter units