The effective nuclear charge is the net positive charge applied to an electron in a polyelectronic atom. It was written with the formula Zeff=ZS where Zeff means the effective nuclear charge, Z is the nuclear charge and S is the average number of electrons between the electron and the nucleus. As the atomic number increases, the Z also increases. This is why Zeff tends to increase with higher atomic number. Hydrogen with the lowest atomic number would have the lowest Zeff
Element H has the smallest effective nuclear charge Further explanation Effective nuclear charge is the nuclear charge which is influenced by the shielding effect of electrons
The effective nuclear charge (Zeff) can be formulated as follows:
with
Z = nuclear charge = atomic number
S = shielding constant
Shielding constants are constants generated by the central attraction of electrons in the inner shell.
Rules for calculating shielding constants S (Slater’s rules)
1. Electrons in orbitals are grouped according to shell /1s/2s, 2p/3s, 3p/3d/4s, 4p/4d/4f/5s, 5p/5d/5f/
2. The electron to the right of the specified electron, shielding constants = 0
3. The electron to the left of the specified electron, (for ns, np orbitals), the shielding constant value: * Electrons in the same shielding effect layer (same ns and np orbitals): 0 .35
* Electrons in the deepest layer (n-1, energy level of the lower layer), shielding effects = 0.85
* Electrons in deepest layer (left of n-1, in layer two energy levels and below) shielding effects = 1.00
4. For def orbitals, electrons in the same group, shielding effects: 0.35, while electrons to the left (at all lower energy levels), shielding effects: 1.00 Elements with atomic numbers 1 to 18 are in periods 1 to 3
If we want to calculate the smallest effective nuclear charge, we determine the electronic configuration of each element
Logically, with the smallest atomic number, the H atom will have the smallest Z eff
H element configuration
H: 1s¹ Z=1
S=0
Z eff = Z – S = 1-0 = 1
So the value of Z eff = Z
Read more The effective nuclear charge
X is the effective nuclear charge and it increases over a period.
The effective nuclear charge of an atom is primarily affected by
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