Classify each statement about effective nuclear charge, Zeff, as true or false. True Effective nuclear charge does not depend on the number of electrons present in an atom. Electrons in an s orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge. A 1s electron in a Be atom has a smaller Zeff than a 1s electron in a Li atom. In a N atom, a 1s electron has a greater Zeff than a 2s electron. False Across a period, as Zeff increases, atomic size increases. Effective nuclear charge increases from left to right across a period on the periodic table.