The electron configuration for an atom is 1s 2s 2p2. how many electrons does the atom have? 2 4 5 6

Idon’t understand this page, can someone ?

This image is an example of a(n) a) atom. b) compound. c) mixture. d) molecule.

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.