Improve your understanding of chemical orbitals

Orbital ooh! It is like orbit and orbit is something round ooh! Not round but spherical. Sometime differentiating round and sphere can be like climbing a steep mountain to majority of human kind. Back to business, it will be very crucial to understand what a shell is and the number of shells which are possible in an atom.  Shell is a spherical space around a nucleus (nucleus of an atom consists of protons and neutrons, except for one of the hydrogen isotopes (protium), which has a nucleus consisting of one proton. The nucleus has a positive electric charge, the size of which depends upon the number of protons it contains. The nucleus provides the mass of an atom); it contains extra-nuclear electrons with energy levels of that shell. An atom possesses different shells of increasing radii around its nucleus. The radius of a shell is 100 000 times greater than the radius of the nucleus.

Ok now let’s focus on these shells of atom. The first one is; K-shell is the innermost atomic shell, it contains only one s-orbital (contains only two (2) electrons). This arrangement completes the shell. This is followed by L-shell which is the next atomic shell to the K-shell; it contains one s-orbital and three p-orbitals that is px, py and pz which contain 2 electrons each (a total of 8 electrons) and this arrangement completes the shell. M-shell is the third shell it is the next atomic shell to the L-shell, it contains one s-orbital, three p-orbitals and five d-orbitals. This means it contains a total of 18 electrons.  This arrangement completes the shell. There are further shells beyond the M-shell and they include: N-shell which is the next atomic shell to M-shell, it contains one s-orbital, three p-orbitals, five d-orbitals and seven f-orbitals thus contains a total of 32 electrons. The next one is O-shell it is the next atomic shell to the N-shell. This contains one s-orbital, three p-orbitals, five d-orbitals and seven f-orbitals and nine g-orbitals this makes it to accommodate a total of fifty (50) electrons. The final one is P-shell this next to atomic O-shell. It contains one s-orbital, three p-orbital, five d-orbitals, seven f-orbitals, and nine g-orbitals and finally eleven h-orbitals. This means it contain a total of 72 electrons.

Now orbital can be understood with easy. Orbital is the space where one or two electrons but not more can exists. The space is where there is a probability of finding one or both electrons. The probability varies over the space, and can be shown in various ways by a diagram. The position and motion of an electron in an orbital cannot be described, only the probability can be described. One way of showing probability is by shading. Another way is by drawing the limits of the orbital, two electrons in an orbital do not interfere with each other; two electrons form a stable orbital, while one electron in an orbital is active in forming chemical bonds. The orbitals commonly taking part in bonds are s-, p- and d-orbitals even though in the above paragraph more of them are addressed. The best way to know the number of orbitals a shell can hold and the number of electrons and orbital can hold is by this;the number of electrons in one orbital to another increases by 4 electrons, for instance  s-orbital can hold 2 electrons while p-orbital can hold 6 electrons. From s-orbital to p-orbital, there is increment of 4 electrons (2+4=6 electrons which occupy three p-orbitals). This is the same with all succeeding orbitals.To get the number of orbitals in a given level of orbital is by adding 2 to the previous level of a given orbital. For example from s-orbital to p-orbital there is addition of 1+2 = 3, and this result in three p-orbitals. This is true from p-orbital to d-orbital, where 3+2 = 5, this results in five (5) d-orbitals. The number of orbitals a shell can contain is achieved by; linear arithmetic progression. From K-shell to L-shell, the orbitals increase by 3. This means L-shell can contain 4 maximum numbers of orbitals (one s-orbital and three p-orbitals). The shell (M-shell) can contain nine (9) numbers of orbitals. Therefore you can use linear arithmetic progression to obtain the number of orbitals a shell can contain in that order. Let’s demonstrate by an example K-shell (1) = L-shell (4) = M-shell (9), in the first difference we have 3, to get the next difference you should add 2 to get 5, now, 4+ 5 = 9. This you can do to the next atomic shell by adding 2 +5 to get seven (7) then seven (7) plus 9 yields 16. Thus the next shell can hold 16 orbitals. Take a look at example below:

  Orbital                                               Maximum number of electrons            Shape      

s (sharp)                                               2                                              Spherically symmetrical

p (principal)                                          6                                              Px , Py ,Pz

d (diffuse)                                            10                                            5 orientations

f (fundamental)                                     14                                            7 orientations