Tin-126 has a half-life of 100,000 years. How many years does it take to reduce a 100 g of Sn-126 to 12.5 g?

Energy defines the different "states" of matter. in no more than 3 sentences, describe the amount of kinetic energy that each of the 3 states of matter possesses and relate that to the atom/molecular motion of each "state".

Sum of brother and sisters age is 26. four times the brothers age is subtracted from three times the sisters age, the difference is 8. what are the ages of the brother and sister?

On the periodic table, elements are arranged by which of the following. a. mass numbers. b. increasing atomic number. c. alphabetical order. or d. density