Classify each statement about effective nuclear charge, Z_eff, as true or false.
ID: 515584 • Letter: C
Question
Classify each statement about effective nuclear charge, Z_eff, as true or false. A 1s electron in a Be atom has a smaller Z_eff than a 1s electron in a Li atom. Electrons in an s orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge. Effective nuclear charge does not depend on the number of electrons present in an atom. Across a period, as Z_eff increases, atomic size decreases. In a N atom, a 1s electron has a greater Z_eff than a 2s electron. Effective nuclear charge decreases from left to right across a period on the periodic table.Explanation / Answer
True
1. electrons in s orbital are more effective than those in other orbitals at sheilding other electrons from the nuclear charge
2. Across a period, as Zeff increases, atomic size decreases.
3. Effective nuclear charge decreases from left to right across a period on periodic table
4. In a atom, a 1s electron has greater Zeff than 2s electrons
Zeff for 1s = 7 -2 = 5
Zeff for 2 s = 7- 4 = 3
False
1. A 1s electron in Be atom has a smaller has smaller Zeff than a 1s electron in a Li atom.
Zeff for Be = 4-2 =2
Zeff for Li = 3-2 =1
2. effective nuclear charge does not depend on the number of electrons present in an atom
as Zeff depends on n average no of electrons present between nucleus and electron in question.