Register to reply

Question about the octet rule

by marc32123
Tags: octet, rule
Share this thread:
Mar28-14, 07:02 AM
P: 18
I read on chemwiki that "The Octet Rule requires all atoms in a molecule to have 8 valence electrons--either by sharing, losing or gaining electrons--to become stable"

Is it true that all atoms in a molecule have 8 electrons by sharing losing or gaining them?
Phys.Org News Partner Chemistry news on
Video: How did life on Earth begin?
Now you can turn your inkjet printer into a chemistry lab and use it to diagnose diabetes
Advanced molecular 'sieves' could be used for carbon capture
Mar28-14, 08:22 AM
P: 435
It is true that this is what the octet rule says[1]. It is not true in reality. First, how to assign electrons to atoms is nowhere near clear. This cannot be done on a purely physical basis, but requires some empirical input. Second, various methods of assigning/counting the electrons based on first principles calculations show that most bonds are quite polar in practice and that even hydrogens and first row main group atoms and tend to have "shared electron numbers" which far deviate from the ideal octets one might think they should have. For higher main group elements and transition metals then all bets are off.

The octet rule is good for rationalizing many compounds, but do not take it too seriously. It is a reasonable model for a broad class of compounds, but it does not reflect reality. What one often sees in practice is that chemists think of very "interesting" ways of counting electrons with the sole purpose of fitting their compounds into the model.

[1] ...for main group compounds. Hydrogen is supposed to acquire two valence electrons, not eight, and d-metals 18

Register to reply

Related Discussions
Question about the Octet rule. Chemistry 8
Octet Rule Biology, Chemistry & Other Homework 8
The Octet Rule Biology, Chemistry & Other Homework 9
Octet Rule Chemistry 20
Octet Rule Biology, Chemistry & Other Homework 2