Ionization energy of Boron is smaller than Beryllium even though effective nuclear charge is higher?

The electronic configurations of Boron and Beryllium are (B [He]1S2,2S2,2p1) and (Be [He]1S2,2S2). In Boron the outermost electron is present in the 2p orbital and is less strongly bound than the electron present in a 2S orbital of Beryllium, which will has a higher Zeff. It is easier to ionize the Boron atom.

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