The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons respectively in their outermost shells. Write the group numbers in which these elements are placed in the Modern Periodic Table. configuration of the atoms of B and D and the molecular formula of the compound formed when B and D combine.
Answer
Group number =
- 10 + number of valence electrons for p block elements
- group number = number of valence electrons for s block elements.
| A | B | C | D | |
| Number of Valence electrons | 1 | 3 | 5 | 7 |
| Group Number | 1 | (10+3)=13 | (10+5)=15 | (10+7)=17 |
The electronic configuration of:
- B will be 2, 8, 3
- D will be 2, 8, 7
Compound formed when B and D combine:
B has a valency of 3 whereas C has a valency of 1.
So, the compound formed by B and D will be BD 3
