The compound is used in medicine as a source of magnesium ions, which are essential for many cellular activities. Magnesium chloride has also been used as a cathartic and in alloys. To low
Assuming it has no electrical charge, your electron count would be equal to the atomic number.
The ideal gas law:

p - pressure, n - number of moles, R - the gas constant, T - temperature, V - volume
The volume and temperature of all three containers are the same, so the pressure depends on the number of moles. The greater the number of moles, the higher the pressure.
The mass of gases is 50 g.

The greatest number of moles is in the container with Ar, so there is the highest pressure.