PHYSICS PLEASE HELP!

If the half life of a given substance is 65 days, how long will it take for a 100-gram sample of the substance to decay until there is only 25 grams of the radioactive material remaining?

if a sample of radioactive isotopes takes 60 minutes to decay from 200 grams to 50 grams, what is the half life of the isotope?

If a 500.0 g sample of technetium-99 decays to 62.5 g of technetium-99 remaining in 639,000 years, what is the half life of technetium-99?

4. now look at the green lines you created by connecting the three boiling point data points and the three melting point data points. for each of these lines, describe any trends you see. 5. locate the elements on your periodic table that you circled in green on your graph. what term or description would you use to identify these elements with respect to the periodic table? 7. using the room temperature line (orange line) and your periodic table, make lists that identify the state of matter (gas, liquid, or solid) in which each element you plotted exists at room temperature. explain your answers.