Why Does Binding Energy Differ Between ^6Li and ^7Li?

[Taylor_1989]

Homework Statement

Q: With reference to the semi-emprical mass formula, explain why one binding energy is greater than the other?

The element in question is $^6 L_i$ & $^7L_i$

Homework Equations

The Attempt at a Solution

So far from what I have read I think the part of the equation they are ref to is the parity part have I got this correct? My issue is I am really trying to understand why it changes I look at the equation more and more and get confused by playing with the number and pluggin them into the equation, I have noticed for a A=7 and Z=3 the binding energy is higher but for A=6 and Z=3 the binding energy is lower. I did read some about odd even, but it did not make sense at the time, but it seem from just the number I plug in, that for odd even you have a lower binding energy than with an odd, odd but why is this?

 

[haruspex]

There's probably a more appropriate forum for this.
Anyway, at https://en.m.wikipedia.org/wiki/Semi-empirical_mass_formula I see a description of pairing energy. Looks relevant.