Question

which describes nuclear fission? (1 point)
starts when a neutron slams into an atom, causing two atoms to form one, heavier atom
starts when two atoms slam together, causing the larger atom to split into two smaller atoms
starts when a neutron slams into an atom, causing the larger atom to split into two smaller atoms
starts when two atoms slam together to form one, heavier atom

Explanation:

To determine the correct description of nuclear fission, we recall the definition: Nuclear fission is the process where a neutron collides with a heavy (larger) atomic nucleus, causing it to split into two (or more) smaller atomic nuclei.

• The first option describes nuclear fusion (combining to form a heavier atom) and has incorrect causation (neutron causing fusion).
• The second option incorrectly states two atoms slamming together to cause fission; fission is initiated by a neutron, not two atoms colliding.
• The third option matches: a neutron slams into an atom (nucleus), causing the larger atom to split into two smaller atoms.
• The fourth option describes nuclear fusion (two atoms forming a heavier atom), not fission.

Answer:

C. starts when a neutron slams into an atom, causing the larger atom to split into two smaller atoms (assuming the options are labeled A, B, C, D with the third option as C; adjust label if needed, but the text of the correct option is "starts when a neutron slams into an atom, causing the larger atom to split into two smaller atoms")