Answer:
3. Equal numbers of protons and neutrons
Explanation:
The nucleus becomes unstable if the ratio of protons to neutrons is less than 1:1 or more than 1:1.5.
The most stable nucleus has a neutron proton ratio of 1:1 which means that they can not release a neutron or a proton to decay.
Nucleus 3 is therefore the most stable.
It's B
because ionic molecules are not soluble in oil
polar molecules are soluble in water
nonpolar molecules are not soluble in water
and metals are not soluble neither in water nor in oil
