Question

what are the two exception to the octet rule you must know in chem 3a?
boron which can have 6 or 8 electrons.
xenon my have 10 electrons
hydrogen which gets a duet (2)
sulfur and phosphorus may have 12 electrons.
there are no exceptions to the octet rule.

Explanation:

• Hydrogen: It has only one electron in its \(1s\) orbital. To achieve a stable configuration, it needs only one more electron to fill its \(1s\) orbital (a duet, since the first shell can hold a maximum of 2 electrons). So, it is an exception to the octet rule (which is about having 8 electrons in the valence shell for most atoms).
• Boron: In many of its compounds (e.g., \(BF_3\)), boron has only 6 electrons in its valence shell. This is because boron has 3 valence electrons and forms 3 covalent bonds (sharing 3 pairs of electrons). While it can sometimes have 8 electrons (in some reaction intermediates or more complex compounds), its common state with 6 electrons makes it an exception to the strict octet - rule requirement of always having 8 electrons in the valence shell for stability.

Answer:

boron which can have 6 or 8 electrons, hydrogen which gets a duet (2)