Effective nuclear charge (Clementi) - 3d nuclear charge units
Consider the third electron in a lithium atom. It is affected by
the charge on the nucleus (+3). However it is also repelled by
the charge on the inner two electrons. Electrons in the 1s
orbital are much closer to the nucleus than any electrons in the
2s or 2p orbital. The two inner electrons in the 1s orbital
screen the third electron from the full effect of the nuclear +3
charge. The difference between the full nuclear charge, Z, and
the screening effect of the inner two electrons is called the
effective nuclear charge, or Zeff. In general, for any many-
electron atom, any particular electron will always be screened
from the nucleus to some extent by the remaining electrons. The
numbers quoted here were calculated using methods known as
"self-consistent-field" (SCF) calculations. You can view values
in a number of graphic styles for electrons contained in the
follwing orbitals: WebElements now has an online chemistry shop
at which you can buy peri