The answer is
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not really sure forgive me if im wrong
Nuclear decay or radioactive decay is a process by which the nucleus of an unstable atom loses energy that is in terms of its mass. The radioactivity may cause an atom to lose whichever of its subatomic particles.
The explanation as why some of the atoms go through nuclear decay while others do not its because of the stability of some atoms. Atoms usually tend to follow octet rule, those which do not follow through this may experience the nuclear decay.
Explanation:
In a voltaic cell, oxidation reaction occurs at anode whereas reduction reaction occurs at the cathode.
Hence, the half-cell reaction taking place at anode and cathode will be as follows.
At anode (Oxidation) :
...... (1)
At cathode (Reduction) : 
So, in order to balance the half cell reactions, we multiply reduction reaction by 3. Hence, reduction reaction equation will be as follows.
........ (2)
Therefore, overall reaction will be sum of equations as (1) + (2). Thus, net reaction equation is as follows.
The purpose is that it shows you all the elements we know and it arranges them in groups that are also the same kind like Chemistry.
Answer:
Nitrogen (N2) are not compounds because each is composed of a single element.