Consider the molecule germanium tetrachloride, GeCl4 The electronegativity values for Ge and I are 1.8 and 3.0, respectively. Based on these values and on consideration of molecular geometry, the Ge bond is and the molecules Hint: Draw Lewis Dot Structure]
a. Polar Covalent: Polar
b. Polar Covalent: Non-Polar c
c Non-Polar Covalent: Non-Polar
d. Non-Polar Covalent, Polar
e. None of the above
The Correct Answer and Explanation is :
The correct answer is a. Polar Covalent: Polar.
Explanation:
To determine the polarity of the bonds and the overall molecule, let’s break down the steps:
- Electronegativity Difference:
The electronegativity of germanium (Ge) is 1.8, and the electronegativity of chlorine (Cl) is 3.0. The difference in electronegativity between these two elements is: [
\Delta \chi = 3.0 – 1.8 = 1.2
] A difference of 1.2 is considered to indicate a polar covalent bond. In a polar covalent bond, electrons are shared unequally between the two atoms, with the more electronegative atom (chlorine in this case) pulling electron density towards itself, creating a dipole. Therefore, each Ge-Cl bond in GeCl4 is polar. - Molecular Geometry:
The molecular geometry of germanium tetrachloride (GeCl4) is tetrahedral. Germanium (Ge) is the central atom surrounded by four chlorine atoms, and each bond is polar due to the electronegativity difference. However, because of the symmetrical tetrahedral arrangement of the molecule, the individual dipoles cancel out. This results in the overall molecule being polar despite the symmetry of the bonds. - Polarity of the Molecule:
While the individual Ge-Cl bonds are polar, the molecule as a whole is polar due to the dipole moments of the bonds not cancelling out entirely. The electronegativity difference (1.2) and the molecular geometry lead to a net dipole in the direction of the chlorine atoms.
Thus, germanium tetrachloride has polar covalent bonds and is a polar molecule.
Summary:
- The Ge-Cl bonds are polar covalent because of the significant electronegativity difference.
- The overall molecule is polar because of the asymmetric nature of the individual bond dipoles in the tetrahedral structure, which results in a net dipole. Therefore, the correct answer is a. Polar Covalent: Polar.