2.2 Intermediate Bonding and Bond Polarity

2.2 Intermediate Bonding and Bond Polarity

1. Electronegativity

   • The measure of attraction of an atom in a molecule for a pair of electrons in a covalent bond
   • The Pauling Scale- electronegativity increases across a period and down a group, making flourine the most electronegative element

2. Ionic and Covalent bonding

   • They are the extremes of a continuum of bonding type
   • To find what degree a bond in a molecule is covalent or ionic, find the difference in electronegativity then use a table to find the result
   • Less electronegative is covalent, more elctronegative is ionic

3. Polar bonds

   • The more electronegative element atom attracts the electron pair more so it will have a delta negative charge whilst the other atom has a lesser share of the elctron pair so has a delta positive charge.
   • A covalent bond in which there is a separation of charge (one end delta negative and the other delta positive)
   • Can only form between two different molecules as two of the same molecules have the same amount of electronegativity so the electron charge is in the middle
   • The more electronegative a molecule, the more the elctron pair will move towards it, making it more ionic than covalent

4. Polar molecules

   • Just because a molecule has polar bonds, it doesn't mean that it a polar molecule
   • Lacks symmetry, is linear, has a single H atom, has an OH at one end, has an end at one end.
   • Uneven distribution of charge- if negative is on the outside and positive on the inside then the molecule will not be polar

5. Non-polar molecule

   • Symmetrical, an element or a carbon compound