Nuclear charge actually experienced by an electron is termed as effective nuclear charge. The effective nuclear charge `Z^(**)` actuall ydepends on type of shell and orbital in which electron is actually present. The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is
`s gt p gt d gt f` (for the same value of n)
The phenomenon in which penultimate shell electrons act as screen or sheild in between nucleus and valence shell electrons and thereby reducing nuclear charge is known as shielding effect. the penultimate shell electrons repel the valence shell electron to keep them loosely held with nucleus. it is thus evident that more is the shielding effect, lesser is the effective nuclear charge and lesser is the ionization energy.
Q. Which of the following is not concerned to effective nuclear charge?

Options

A. Higher ionization potential of carbon than boron
B. Higher ionization potential of magnesium than aluminium
C. Higher values of successive ionization energy
D. Higher electronegativity of higher oxidation state

Explanation

To determine which of the following options is not concerned with effective nuclear charge, we need to analyze each option in relation to the concept of effective nuclear charge (Z^eff) and its implications on atomic properties such as ionization energy, electronegativity, and oxidation states.

### Step-by-Step Solution:

1. **Understanding Effective Nuclear Charge (Z^eff)**:
- Effective nuclear charge is the net positive charge experienced by an electron in a multi-electron atom. It accounts for the shielding effect caused by other electrons.
- The formula for effective nuclear charge can be approximated as:
\[ Z^{eff} = Z - S \]
where \( Z \) is the actual nuclear charge (number of protons) and \( S \) is the shielding constant (number of inner electrons).

2. **Analyzing the Options**:
- **Option A: Higher ionization potential of carbon than boron**:
- Carbon has a higher ionization potential than boron due to its smaller atomic size and higher effective nuclear charge. This option is concerned with effective nuclear charge.

- **Option B: High ionization potential of magnesium and aluminum**:
- Magnesium has a stable electron configuration (full s subshell) compared to aluminum (which has an unpaired p electron). The stability of the electron configuration plays a more significant role in determining ionization energy than effective nuclear charge in this case. Thus, this option is less concerned with effective nuclear charge.

- **Option C: Higher values of successive ionization energies**:
- Successive ionization energies increase due to the increase in effective nuclear charge as electrons are removed. This option is concerned with effective nuclear charge.

- **Option D: Higher electronegativity of higher oxidation states**:
- Higher oxidation states generally lead to a smaller ionic size and a higher effective nuclear charge, resulting in increased electronegativity. This option is also concerned with effective nuclear charge.

3. **Conclusion**:
- The option that is not concerned with effective nuclear charge is **Option B**: High ionization potential of magnesium and aluminum.

### Final Answer:
**Option B**: High ionization potential of magnesium and aluminum is not concerned with effective nuclear charge.

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