(a) The mirror isobar of is

(b) has a greater binding energy than that of

Explanation

(a).

Mirror isobars are isobars whose mass number is same and the number of protons of is equal to the number of the neutrons of and the number of neutron of is equal to the proton of the . Therefore, the mass number of both the elements is

So according to mirror isomers

Then the mass number can also be formed as

Now to find the mirror isobar of nuclide, we know that mass number of sodium (Na) = 23, and another similar case is that of Magnesium (Mg) = 23, with sodium has 11 proton and 12 neutron and magnesium with 12 proton and 11 neutron.

(b).

To find the binding energy of the elements of Sodium and Magnesium; we use the formula for calculation of Binding energy from mass defect.

To find the value of atomic mass of an element we use:

where

is the number of proton, is the number of neutrons, the mass of a single proton = , the mass of a single neutron is

So firstly for Sodium,

We need the actual mass of Sodium which is

The atomic mass of Sodium is from the calculation of proton and neutrons is

To convert the mass defect into we multiply it by

Therefore, the Binding Energy of the element Sodium is

Similarly for Magnesium, we get the Binding Energy as

We need the actual mass of Magnesium which is

The atomic mass of Magnesium is from the calculation of proton and neutrons is

To convert the mass defect into we multiply it by Therefore, the Binding Energy of the element Magnesium is

Hence, as we can see that the Binding energy of magnesium is greater than that of Sodium, the is another reason apart from the value is because of the number of proton present in the nucleus, even number of protons tends to have more Binding Energy than that of odd number of protons.