Covalent Bonding (Molecular Compounds) Subtitle

Properties of a Covalent Bond Formed when at least one pair of electrons are shared between non-metals Can be equal sharing (50-50) and if so is called non-polar Or unequal sharing (based on electronegativity difference) and is called polar All elements involved still obey the octet or duet rule when the compound is formed

Properties of Covalent Compounds Weak bonds Soft solids, or liquids, or gases at room temperature Low melting points, and low boiling points Share electrons not exchanging Polar Covalent will dissolve in water Non-Polar covalent will not dissolve in water Do not conduct electricity

Continuing Properties Each element the in compound have 8 valence electrons when completed Non-polar covalent substances will dissolve in non-polar covalent liquids

Types of Covalent Compounds (Molecular) Single Covalent Bonds Formed by the sharing of one pair (2 total) of electrons Most common type of covalent bond Weakest type of covalent compound

Types Continued (Double Covalent Bonds) Formed by the sharing of 2 pairs (4 total) of electrons Stronger than a single bond, better at distributing energy and much harder to break apart

Types Continued: Triple Covalent Bond Formed by the sharing of 3 pairs of electrons (6 total) Strongest type of covalent bond that exists Provides stability and is very hard to break apart

Bond Polarity Only applies to Covalent Compounds (molecular) and never to an ionic compound Polarity tells us which part of our molecule has a slight negative charge, and which part has a slight positive charge Polarity is based on electronegativity difference between the elements Elements that have higher electronegativity values will become the negative end of the molecule Elements with the lower electronegativity will become the positive end of the molecule

Non-Polar Covalent Bond Formed between 2 elements when the electronegativity difference is All diatomics are non-polar in terms of bonding To be non-polar means that no element is strong enough to share in a way that makes the bond uneven from a distribution of charge standpoint

Polar Covalent Bond Bond that is formed when the electronegativity difference between the elements is between 0.4 and 1.7 Still a covalent bond but the sharing of the electrons is unequal More electronegative element will have the shared electron pair more often in its area than the element with the lower electronegativity The more electronegative element will take on a slight negative charge The less electronegative element will take on a slight positive charge