The second ionisation energies are higher than the first ionisation energies. This is mainly due to the fact the after the removal of the first electron, the atom changes into monovalent positive ion. In the ion, the number of electrons decreases but the nuclear charge remains the same. as a result of this, the remaining electrons are held more tightly by the nucleus and it becomes difficult to remove the second electron. therefore, the value of second ionisation energy. `(IE_(2))`, is greater than that of the first ionisatio energy `(IE_(1))`. similarly third ionisation energy `(IE_(3))` is greater than that of second `IE_(2)`.
Q. Successive ionisation energy of an atom is greater than previous one, because:

Options

A. `p/e` ratio increases
B. `p/e` ratio decreases
C. `p/e` ratio remains constant
D. none of these

Answer

To answer the question regarding why successive ionization energies of an atom are greater than the previous one, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding Ionization Energy**:
- Ionization energy is the energy required to remove an electron from an atom or ion in the gas phase. The first ionization energy (IE₁) refers to the removal of the first electron, while the second ionization energy (IE₂) refers to the removal of the second electron.

2. **Initial State of the Atom**:
- In a neutral atom, the number of protons (positive charges) is equal to the number of electrons (negative charges). This balance creates a stable configuration.

3. **First Ionization**:
- When the first electron is removed, the atom becomes a positively charged ion (monovalent positive ion). The number of electrons decreases, but the number of protons remains unchanged.

4. **Effect on Remaining Electrons**:
- After the removal of the first electron, the remaining electrons experience a stronger effective nuclear charge because there are fewer electrons to shield them from the nucleus. This means that the remaining electrons are held more tightly by the nucleus.

5. **Second Ionization**:
- When the second electron is removed, the ion is now a divalent positive ion. Again, the number of electrons decreases while the number of protons remains the same, leading to an even stronger attraction between the nucleus and the remaining electrons.

6. **Successive Ionization Energies**:
- This pattern continues with each successive ionization. As more electrons are removed, the ratio of protons to electrons (p/e ratio) increases. With fewer electrons to shield the nucleus, the remaining electrons are held more tightly, resulting in higher ionization energies for subsequent removals.

7. **Conclusion**:
- Therefore, the successive ionization energies (IE₂ > IE₁, IE₃ > IE₂, etc.) are greater than the previous ones primarily because the effective nuclear charge felt by the remaining electrons increases as electrons are removed.

### Final Answer:
The successive ionization energy of an atom is greater than the previous one because the number of electrons decreases while the number of protons remains constant, leading to an increased effective nuclear charge on the remaining electrons.