Detailed calculations show that the value of Zeff for the outermost electrons in Na and K atoms is 2.51+ and 3.49+ , respectively.
What value do you estimate for Zeff experienced by the outermost electron in both Na and K by assuming core electrons contribute 1.00 and valence electrons contribute 0.00 to the screening constant? What values do you estimate for Zeff using Slater’s rules?
Does either method of approximation account for the gradual increase in Zeff that occurs upon moving down a group?