In an atom: The nucleus is made of electrons and protons.
Protons have positive charges.
Neutrons have negative charges.
All of the above.
can someone please help me ived this 2 times

Explanation:

The nucleus of an atom contains protons and neutrons.

Protons have positive charges, neutrons have neutral charges (no charge), and electrons have negative charges.  That is why when you determine net charge of atom you only look at the proton to electron ratio since the neutrons don't matter when it comes to charge.

I hope this helps.  Let me know in the comments if anything is unclear.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.