Formation of a Hydrogen Molecule
More simply, an electron pair can be represented by a dash.
H-HFormulas drawn with Lewis symbols are called Lewis formulas or Lewis structures, or more simply structural formulas. They show which atoms are present and how they are connected into each other.
An octet is formed on the chlorine atom and the maximum pair on the hydrogen atom. Here is the bonding of a chlorine molecule (Cl2):
An octet is formed on the two chlorine atoms.
When the two N atoms share electrons they have to share 3 pairs to add to their 5 electrons to complete their octet.
Double bonds occur in carbon dioxide (CO2):
If it is placed in an acidic solution (a proton donator), H+ ions (protons), the ammonia takes in the proton and becomes NH4+, an ammonium ion. The H+ ion has a vacant 1s orbital in its valence shell and can accomodate two electrons. The two unshared pair of electrons in the ammonia can be donated to the H+.
An arrow from the nitrogen atom to the hydrogen ion indicates that the nitrogen is sharing it pair of electrons with it. This sharing is called an coordinate covalent bond.