Question

Second ionisation enthalpy of copperand chromium high give reason

Answer 1

electronic config of copper: [Ar] 3d10 4s1

electronic config. of chromium: [Ar] 3d5 4s1

by electronic config, the first ionisation enthalpy will be low because s orbital will readily lose the electron. but removing electron from d orbital will be tough because chromium and copper are stable ( due to half and full stability respectively)

it will require high amount of energy to remove the electron and make the already stable atom, unstable. therefore second ionisation enthapy is high.