In a different experiment, a student places a piece of pure ba(s) in a beaker containing 250.ml of 6.44mhcl(aq) and observes that the rate of appearance of h2(g) bubbles when ba(s) was added is much faster than the rate of appearance of bubbles when the mg(s) was added. the student claims that the greater reactivity is due to the difference in ionization energy between mg and ba. explain the difference in ionization energy between mg and ba in terms of atomic structure.

The Ionization energy  of Barium is lower and hence it can lose its electrons easily.

Explanation:

Ionization energy is defined as the energy required to remove an electron from an isolated gaseous atom. It is represented as

This energy will be higher for fully filled and half-filled electronic configuration than partially filled electronic configuration. This is so because half filled and fully filled configurations are stable.

Magnesium is the 12th element of the periodic table having electronic configuration of =

Barium is the 56th element of the periodic table having electronic configuration of

Both magnesium and barium belong to the same group as they have similar valence electrons. But as Barium is larger in size, the valence electrons lie farther from the nucleus and lesser energy is required to remove the electron and thus ionization energy will be lower for barium and thus will be more reactive.

The difference in the ionization energy results as barium is larger in size than Magnesium. The bigger size element requires less energy to remove the outermost electron and thus has lesser ionization energy.

The ionization energy can be described as the energy required to remove the outermost electron. The Mg and Ba both belong to the same group and have the same electronic configuration. Thus, the difference in ionization energy can not be in the terms of differences in valence electrons.

The Mg and Ba both belong to the same group, but the size of Ba is larger than Mg. The larger size results in the outermost electron being away from the nucleus, and the force acting on the electrons has been less. Thus the ionization energy of Ba is lesser as compared to Mg.

For more information about the ionization energy, refer to the link:

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