<h2>
Answer:</h2>
True answers would be B, C, and D.
<h3>
Explanation:</h3>
A: <u>This statement is not true.</u> The "splitting" that is seen in nuclear reactions is shown in the nucleus of an atom, not the atom itself splitting.
B: <u>This statement is true</u>, see the equation I created below, which illustrates the creation of oxygen atoms.
4He^2+14N^7→17O^8+1H^1
C: <u>This statement is true.</u> In nuclear fission, one form of a nuclear reaction, an atom's nucleus is split into smaller parts, which quite obviously affects the nucleus, seeing as it is now in several parts.
D: <u>This statement is true.</u> We know this because of the well known equation created by Einstein, E = mc2. In a nuclear reaction, mass is not strictly conserved. Some of the mass is converted into energy.
I hope this was helpful! Let me know if you need any further explanation. I tried my best to thoroughly explain this, as I have background in this sort of education.
