Octet rule
|
|
Missing image
Octeto.png
Octeto.png
This combination occurs primarily in two ways, electrovalent bonding and covalent bonding.
Some of the atoms for which the octet rule are most useful are:
However, the exceptions are plenty:
- hydrogen only needs one electron to have a noble gas structure (that of helium), and lithium needs to lose one.
- any molecule or ion with an odd number of electrons
- any atom that forms more than four bonds (phosphorus falls under this as well as the rule below)
- the octet rule is inapplicable to atoms in periods greater than 2 because their electron shells can hold more than eight electrons. See hypervalency
- For Transition metals an alternative for the octet rule is electron counting.
- boron is an exception with extreme frequency
- there are a few special cases in very common substances, notably carbon monoxide and ozone