octet exceptions

[Nicholas Kull_3L]

What are elements with octet exceptions and why do these occur?

[Rithana Srikanth 3L]

Elements that can have expanded octet include P, S, Cl - elements from Period 3 and beyond. This is because these elements have d-orbitals that can expand to accommodate more electrons.

[Tuong Nguyen 2I]

The first four elements (H, He, Li, Be) can have an incomplete octet since their electrons only pertain to the s-orbital which requires two electrons to be stable. Group 13 (B, Al, etc.) can also have an incomplete octet because that is just the exception that we need to know about. Any element in Period/Row 3 or further is allowed to have an expanded octet because they have an empty d-orbital in which they can store more electrons in.

[Hanniel U 2B]

The first four elements on the periodic table are elements with octet exceptions.

[JT Wechsler 2B]

The first four elements and group 13 elements all can have less than a completed octet. If an element is in period 3 or lower on the periodic table, then they can have greater than 8 electrons because of the d suborbital.