The half-life of Th-234 is 24 days. How many days will it take to reduce 600 grams of the radioactive element to 150 grams? *

At room temperature what happens to the average kinetic energy of the molecules of a solid, liquid, and a gas

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.

How many neutrons does an element have if its atomic number is 50 and its mass number is 166