the half-life of i-124 is 4.2 days. how long will it take for the mass of i-124 to drop from 10.0 mg to 3.50 mg?

Describe the particles of all three phases of matter in the root beer float. (how are the particles arranged and moving? )

1) this is the structure in the cell nucleus that houses a cell's genetic information

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.