Let’s see the detail behind this
1. In case of Chromium
In case of Chromium, its configuration is d⁶ , after loosing an electron it attains the d⁵ configuration. Now this configuration has half filled d orbital which makes it stable thus we will need more energy.
2. In case of copper
Now in this case we get d¹⁰ configuration on loosing one electron , thus it is hard to remove one more electron from d-subshell. Thus it increases the second ionisation enthalpy.