Chapter 1: Structure Determines Bonding |
Answers to Questions relating to Bonds and Bond Polarity
1. What types of bond exists between the atoms in a molecule of methyl lithium, CH3Li ?
The formula for this compound can be written as [CH3-][Li+] because the metal is very electropositive compared to the carbon atom (if we look at their electronegativities, C = 2.5, Li = 1.0). The [CH3-] group, a methyl anion, has covalent bonds between carbon and hydrogen. Though there is no significant bond polarity to a C-H bond there is a molecular polarity to the anion because of the negative charge placed on carbon. The attraction of the Li+ cation to CH3- is essentially ionic.2. What types of bonds exist between the atoms in a molecule of sodium sulfate, Na2SO4 ?
The formula for this compound can be written as [Na+]2[SO42-], the sulfate anion is formed by covalent bonding between sulfur and oxygen. Since there is a bond polarity to a S-O bond these are polar covalent bonds. The attraction of the Na+ cations to SO42- is ionic.3. What types of bonds exist between the atoms in a molecule of chlorine gas, Cl2 ?
A non-polar covalent bond exists between the atoms in a molecule of Cl2.4. What are all the bond polarities in a sodium acetate molecule, CH3COONa ?
The structure is shown as the resonance hybrid (so both O atoms have equal partial -ve charges).
The most significant polar bonds are the CO bonds.
Since H and C have very similar electronegativities (2.2 and 2.5 respectively), the CH bonds are essentially non-polar.