Successive ionization energies data (in eV/atom) of an element of second period is
`{:(IE_1, IE_2, IE_3, IE_4, IE_5, IE_6),(120,133,167,719 ,797,850):}`
  Find the group number of element according to long form periodic table (1 - 18 convention) 

Answer

To find the group number of the element based on the provided successive ionization energies, we can follow these steps:

### Step-by-Step Solution:

1. **Analyze the Given Ionization Energies**:
The successive ionization energies provided are:
- IE1 = 120 eV
- IE2 = 133 eV
- IE3 = 167 eV
- IE4 = 719 eV
- IE5 = 797 eV
- IE6 = 850 eV

2. **Identify the Pattern in Ionization Energies**:
- The first three ionization energies (IE1, IE2, IE3) show a relatively small increase, which indicates that it is relatively easy to remove the first three electrons.
- A significant jump occurs between IE3 (167 eV) and IE4 (719 eV). This large increase suggests that removing the fourth electron is much more difficult than removing the first three.

3. **Determine the Number of Valence Electrons**:
- The fact that the first three electrons can be removed with relatively low energy suggests that the element has three valence electrons.
- The large jump to the fourth ionization energy indicates that after removing three electrons, the element achieves a stable electronic configuration, making it much harder to remove the fourth electron.

4. **Relate Valence Electrons to Group Number**:
- Elements in the periodic table are grouped based on their valence electrons.
- The element with three valence electrons belongs to Group 13 (or IIIA) of the periodic table, which corresponds to the boron family.

5. **Conclusion**:
- Therefore, the element with the given ionization energies is in Group 13 of the long form periodic table.

### Final Answer:
The group number of the element according to the long form periodic table is **Group 13**.