Question

Why the cu size is lesser than Na...? Thn how the cu shielding... Effect is less compared to Na?

Answer 1

●The size of CU is lesser than Na because Cu have 11 electrons in outer most orbit (2,8,8,11) .. so nucleus have more attraction field to 11 -e ( electrons).. thats why it shrinks in size and Na have 1 electron in outer most orbit (2,8,1) so it have less attraction force between electron and nucleus..

● Shielding effect --
the decrease in attraction between an electron and the nucleus in any atom with more than one electron shell. The more electron shells there are, the greater the shielding effect experienced by the outermost electrons.. thats why Cu have lesser shielding effect because Na has only 1 electron in outer most orbit ..