The bromine atom possesses 35 electrons. It contains 6 electron in 2p orbitals, 6 electrons in 3p orbitals and 5 electrons in 4p orbitals. Which of these electron experiences the lowest effective nuclear charge?

The bromine atom possesses 35 electrons. It contains 6 electron in 2p

1.	The bromine atom possesses 35 electrons. It contains 6 electron in 2p orbitals, 6 electrons in 3p orbitals and 5 electrons in 4p orbitals. Which of these electron experiences the lowest effective nuclear charge?
Answer» SOLUTION :4p electrons, being farthest from the nucleus, experience the lowest effective NUCLEAR charge. For calculation of exact effective nuclear charge, These may be applied to bromine ATOM as follows: `._(35)Br = (1s^(2)) (2s^(2) 2p^(6)) (3s^(2) 3p^(6)) (3d^(10)) (4S^(2) 4p^(5))` For `2p^(6), " " S = (0.35 xx 7) + (0.85 xx 2) = 2.45 + 1.70 = 4.15` `Z_("eff")` for 2p electron `= 35 - 4.15 = 30.85` For `3p^(6), S = (0.35 xx 7) + (0.85 xx 8) + (1.0 xx 2) = 2.45 + 6.80 + 2.0 = 11.25` `Z_("eff")` for 3p electron `= 35 - 11.25 = 23.75` For `4p^(5), " " S = (0.35 xx 6) + (0.85 xx 18) + (1.0 xx 10) = 2.10 + 15.30 + 10.0 = 27.40` `Z_("eff")` for 4p electron `= 35 - 27.40 = 7.60` Thus, 4p has the lowest effective nuclear charge