element 106 has a half life of 0.9 seconds. if 250.0 grams of it were prepared how many grams will remain after 4.5 seconds​

If the particles in a sample of matter have an orderly arrangement and move only in place, the sample is a

The mass of a neutron is equal to the mass of a proton plus the mass of an electron. true or false false true

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.