Why are atoms stable when they achieve an octet or duplet electronic configuration??

Question

You might say that its just nothing and its just an observation.........but what's the secret behind this number '8'??? There must be some reason for each and everything happening in the universe......

Answer 1

The MCAS model does explain why. It is a matter of placing electrons symmetrically around a nucleus. As the nuclear charge increases, electrons are held more tightly and the intermediate space becomes more highly filled with electrons with as symmetrical a distribution as possible. The MCAS is a "cubic" (8-corners!) distributed electon system, as opposed to the primarily x, y, z axes (6-directions!)distribution of the currently accepted spdf model. Also how do you think 7-f orbitals are uniformly distributed? Strange!

Answer 2

An element's valence shell is full and most stable when it contains eight electrons, corresponding to an s2p6 electron configuration. This stability is the reason that the noble gases are so unreactive. Note that a "full shell" means that there are the eight electrons in the valence shell when the next shell starts filling, even though higher subshells (d, f, etc.) have not been filled. There can be at most eight valence electrons in a ground-state atom because p subshells are always followed by the s subshell of the next shell. This means that once there are 8 valence electrons (when the p subshell is filled), the next additional electron goes into the next shell, which then becomes the valence shell.

A consequence of the octet rule is that atoms generally react by gaining, losing, or sharing electrons in order to achieve a complete octet of valence electrons.

Answer 3

Orbital theory predicts it pretty well.

Answer 4

the energy level of each shell or orbit is fixed and the no. of electrons an orbit can hold is 2n^2 where n is the orbit no. since the energy level is fixed an electron jumps to gain or loose energy during the transfer in a chemical reaction. once the optimum energy level of a particular orbit is achieved it no longer can accomdate any electron. so 1st orbit 2,second 8, third 18,generally we deal with low level elements so we see duplets and octates as stable configuration.