To draw the Lewis structure for ClF3 (chlorine trifluoride), follow these steps:
- Count the total number of valence electrons: Chlorine (Cl) has 7 valence electrons, and each fluorine (F) atom has 7 valence electrons. Since there are three fluorine atoms, the total number of valence electrons is 7 (Cl) + 7 × 3 (F) = 28 electrons.
- Place the least electronegative atom in the center: Chlorine is less electronegative than fluorine, so it will be the central atom.
- Connect the central atom to the surrounding atoms with single bonds: Draw single bonds between chlorine and each fluorine atom. This uses 6 electrons (3 bonds × 2 electrons).
- Distribute the remaining electrons: After forming the bonds, 22 electrons remain. Place these as lone pairs around the fluorine atoms to satisfy the octet rule. Each fluorine atom will have 3 lone pairs (6 electrons), using up 18 electrons. The remaining 4 electrons will be placed as two lone pairs on the chlorine atom.
Now, let’s answer the specific questions:
a. Formal charge for each atom:
- Chlorine (Cl): Formal charge = 7 (valence electrons) – 2 (lone pairs) – 3 (bonds) = +2
- Fluorine (F): Formal charge = 7 (valence electrons) – 6 (lone pairs) – 1 (bond) = 0
b. Total number of electron domains: There are 5 electron domains around the chlorine atom (3 bonding pairs and 2 lone pairs).
c. Electron geometry: The electron geometry is trigonal bipyramidal due to the 5 electron domains.
d. Molecular geometry: The molecular geometry is T-shaped, as the two lone pairs on chlorine occupy two of the equatorial positions, leaving the three fluorine atoms in a T-shaped arrangement.
e. Polarity: ClF3 is a polar molecule due to the asymmetrical distribution of electron density caused by the lone pairs on chlorine and the T-shaped geometry.