Question

Give the number of pairs of valence electrons for bi3?

1) 8
2) 12
3) 11
4) 18
5) 10

Answer 1

The molecule
`$\mathrm{BI}_3$` has 12 pairs of valence electrons, and the correct answer is (c) 12.

To determine the number of valence electrons for a molecule, you need to consider the valence electrons of each individual atom in the molecule.

Boron (B) is in Group 13 of the periodic table, and it has 3 valence electrons.

Iodine (I) is in Group 17 of the periodic table, and it has 7 valence electrons.

For
`$\mathrm{BI}_3$`, there is one boron atom and three iodine atoms. Therefore, the total number of valence electrons is:

`\[1 * (\text{valence electrons of boron}) + 3 * (\text{valence electrons of iodine})\]`

`\[1 * 3 + 3 * 7 = 3 + 21 = 24\]`

So, there are 24 valence electrons in
`$\mathrm{BI}_3$`.

Now, since each bond involves two electrons, you divide the total number of valence electrons by 2 to get the number of pairs of valence electrons:

`\[(24)/(2) = 12\]`

Therefore, the correct answer is (c) 12.