Bonding in Alkanes
- Alkanes are a homologous series made up of saturated hydrocarbons (containing only hydrogen and carbon) which are joined by sigma (σ) bonds
- They have a general formula of CnH2n+2
- The electronegativities of carbon and hydrogen are very similar so the C-H sigma (σ) bonds are non-polar
- As a result of this, alkanes are nonpolar molecules and have no partial positive or negative charges (δ+ and δ- respectively)
- Alkanes therefore do not react with polar reagents
- They have no electron-deficient areas to attract nucleophiles
- And also lack electron-rich areas to attract electrophiles
- Alkanes therefore do not react with polar reagents
- Given that each carbon has four valance electrons, each carbon atom forms four covalent bonds
- This results in a tetrahedral bonding arrangement with a bond angle of 109.5 o
- Alkanes are non-polar and therefore only exhibit weak temporary induced dipole-dipole forces between the molecules
- As the bond length of the alkane molecule increases the boiling point also increases
Homologous Series of Alkanes