28) Which of the following is true about the modern model of the atom? A) Electrons orbit the nucleus in shells at fixed distances
B) Protons, neutrons, and electrons are located in the nucleus.
C)Atoms are hard, indivisible spheres.
D)A positive nucleus is surrounded by negative electrons.

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.

Drug abuse will not lead to physical and psychological dependence. true or false ?

An object displaces 652 ml of water. the volume of the object is: 0.652 cm³ 6.52 cm³ 65.2 cm³ 652 cm³