A covalent bond is?
A covalent bond is a bond formed by a shared pair.
Explain the forces involved and overcome in a covalent bond.
- The negatively charged electrons are attracted to the positive charges of both nuclei.
- This attraction overcomes the repulsion between the two positively charged nuclei.
Is a covalent bond directional ?
Yes
Draw the dot and cross diagram for H2O
Draw the dot and cross diagram for the covalent bonding of NH3.
What is a lone pair?
A lone pair is an outer-shell pair of electrons that is not involved in chemical bonding.
Note:
Lone pair are concentrated regions of negative charge.
Draw the dot and cross diagram for CO2
What is a dative covalent or coordinate bond?
A dative covalent or coordinate bond is a shared pair of electrons which has been provided by one of the bondinbg atoms only.
Draw how a dative covalent bond can be indicated in a diagram.
Instead of A-B, it would be A->B
Draw the dot and cross diagram for an ammonium ion.
Draw the ammonium in using the elemeny symbols.
Note:
- Once formed, a dative covalent bond is equivalent to all the other covalent bonds.
- For example, in the NH4*ion, you cannot tell which bond was formed from the N lone pair.
How many covalent and dative bonds does an ammonium ion have?
1) Three covalent bonds
2) One dative covalent bond.
What is the oxonium ion?
When an acid is added to water, water molecules form oxonium ions, H3O*. For example, hydrogen chloride gas froms hydrochloric acid when added to water:
HCl(g)+H2O(l)—->H3O*(aq)+CL-(aq)
H3O* ions are responsible for reactions of acids. In equations, the oxonium ion is often simplified as H*(aq).
Why might the outer electrons surrounding an atom in covalent bonding may not follow the octet rule?
- There may not be enough electrons to reach an octet.
- More than four electrons may pair up in bonding.(expansion of the octet.)
