Explanation:
In a magnetic field, the radius of the charged particle is as follows.
r = 
where, m = mass, v = velocity
q = charge, B = magnetic field
Therefore, q will be calculated as follows.
q = 
= 
= 
= 
= +2e
Thus, we can conclude that the charge of the ionized atom is +2e.
Because they have a full outer shell and they are both noble gases...Because the outer shell has attained stable electronics configuration of octate rule this it is with noble gas as helium.
Hope I helped!
So calculate the H for the other two reactions a room temperature and combine the reactions to calculate the H of the decomposition of calcium carbonate using the Hess's Law