[xe] 6s power of 2 4fpower of 4
how does the octet rule applies to covalent bonds?
[Xe]6s24f4 (Neodymium) is too heavy of an atom to have the octet "rule" apply. Typically the octet rule is used to describe the association of lighter atoms that have only s and p orbitals involved in covalent bonding (for the record it's ns2np6). 2 electrons in the s subshell and 6 for the p make a full octet and achieve a noble gas configuration. As Ame mentioned, atoms will covalently "share" electrons in order to have both of them get to this stable state.
There are numerous violations to the octet rule of course, making it more of a rule of thumb than an absolute.
Two covalently bonded atoms share a pair of electrons in their outer shell. Each atom contributes one electron to an electron pair, basically adding one electron to their outer shell in the process.
What is your question regarding Xenon?