2.1.3 [Covalent bonding] Flashcards
What is covalent bonding?
Covalent bonds form between 2 non metals. Strong electrostatic attraction between 2 nuclei and the shared pair of electrons the electrons are shared in order to form full outer shell.
How do covalent bonds formed?
A covalent bond is formed between 2 atoms when an atomic orbital containing a single electron from one atom overlaps with an atomic orbital also containing a single electron of another atom. The atomic orbitals involved can be any of those found in the atoms.
What do these overlaps show?
An end on overlap leads to the formation of sigma bonds. Leads to the formation of a single covalent bond - 2 electrons in the overlap
Sideways overlap of 2 p orbitals leads to formation of pi bonds. Can only be formed when a sigma bond has been formed so pi ponds only exist between atoms that joined by double or triple bonds.
What is bond length?
The bond length is the distance between nuclei of the 2 atoms that are covalently bonded together.
What is bond strength?
The strength of a covalent bond is measured in terms of the amount of energy required to break one mole of the bond in the gaseous state.
What is the relationship between bond length and bond strength?
The general relationship between bond length and bond strength for bonds that are of similar nature. Shorter the bond the greater the strength. This is a result of an increase in electrostatic attraction between the 2 nuclei and electrons in the overlapping atomic orbitals
What is the explanation for bond length vs bon strength
The length of a covalent bond is strongly linked to its strength. Shorter bonds tend to be stronger as the atoms are help closer together so the forces of attraction are greater, requires more energy to overcome. Double and triple bonds are shorter than single covalent bonds explaining why they are so much stronger
