A nuclide 1 is said to be the mirror isobar of nuclide 2 if `Z_(1) =N_(1)` and `Z_(2) =N_(1)`. (a) What nuclide is a mirror isobar of `underset(11)overset(23).` Na ? (b) which nuclide out of the two mirror isobars have greater binding energy and why?

Explanation

According to question a nuclide 1 is said to be mirror isobar of nuclide 2 if `Z_(1) = N_(2)` and `Z_(2) N`
Now in `._(11)Na^(23),Z_(1) =11 N_(1)=23 -11 =12`
`:.` Mirror isobar of `._(11)Na^(23) " is " ._(12)Mg^(23)` for which `Z_(2) =12 =N_(1)" and " N_(2) =23 -12 =11 =Z_(1)`
(b) As `underset(11)overset(23).` Mg contains even number of protons (12) against `underset(11)overset(23).`Na which has odd number of protons (11), therefore `underset(11)overset(23).`Mg has greater binding energy the `._(11)Na^(23)`