The shape of BF species is

Options

A. Tetrahedral
B. Square planar
C. Trigonal planar
D. Linear

Answer

To determine the shape of the BF4- species, we can follow these steps:

### Step 1: Identify the central atom and its valence electrons
- The central atom in BF4- is Boron (B).
- Boron is in Group 13 of the periodic table and has 3 valence electrons.

### Step 2: Account for the charge of the species
- The BF4- species has a -1 charge, which means that Boron has gained an additional electron.
- Therefore, Boron effectively has 4 valence electrons (3 from Boron + 1 from the charge).

### Step 3: Determine the number of surrounding atoms
- In BF4-, there are 4 Fluorine (F) atoms bonded to the Boron atom.

### Step 4: Calculate the steric number
- The steric number is calculated as the sum of the number of sigma bonds and the number of lone pairs on the central atom.
- Here, Boron forms 4 sigma bonds with the 4 Fluorine atoms and has no lone pairs.
- Thus, the steric number = 4 (4 sigma bonds + 0 lone pairs).

### Step 5: Determine the hybridization
- The hybridization can be determined based on the steric number. A steric number of 4 corresponds to sp3 hybridization.

### Step 6: Determine the molecular shape
- With sp3 hybridization and a steric number of 4, the molecular shape is tetrahedral.

### Step 7: Determine the bond angles
- In a tetrahedral geometry, the bond angles are approximately 109.5 degrees.

### Conclusion
- Therefore, the shape of the BF4- species is tetrahedral with bond angles of about 109.5 degrees.

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