how many electrons pairs surround an atom of boron (B,element 5) bonded in the compound BCI3?
three pairs. Boron Chloride is an exception to the rule of eight.
http://www.chemistryexplained.com/Te-Va/Valence-Bond-Theory.html
To determine the number of electron pairs surrounding an atom of boron (B) in the compound BCl3, we need to consider its electron pair geometry.
First, we find the valence electrons for boron by referring to its position in the periodic table. Boron belongs to Group 13, so it has 3 valence electrons (5 - Group number).
Next, we consider the compound BCl3. Chlorine (Cl) belongs to Group 17 and has 7 valence electrons. Since we have three chlorine atoms bonded to the central boron atom, we add 3 times the valence electrons of chlorine to the valence electrons of boron.
Valence electrons of boron (B): 3
Valence electrons of chlorine (Cl): 7 (for each Cl)
Total valence electrons: 3 + (7 x 3) = 24
Now, using the valence electrons available, we can determine the electron pair geometry using the following guidelines:
- 2 electron pairs: linear
- 3 electron pairs: trigonal planar
- 4 electron pairs: tetrahedral
In this case, we have 24 valence electrons, which corresponds to 12 electron pairs. Since the compound BCl3 has a trigonal planar molecular geometry, we can conclude that there are 3 electron pairs surrounding the boron atom.
To determine the number of electron pairs surrounding an atom, you need to know its electron geometry and the number of lone pairs and bonding pairs around it.
Let's start by identifying the electron geometry of boron (B) in the BCl3 compound.
In BCl3, boron (B) is surrounded by three chlorine (Cl) atoms. The central boron atom forms three bonds with three chlorine atoms, resulting in a trigonal planar electron geometry.
The trigonal planar electron geometry consists of three bonding pairs arranged in a flat triangle around the central atom.
In this case, there are no lone pairs of electrons around the boron atom. So, the answer is zero lone pairs of electrons and three bonding pairs surrounding the boron atom.