electron shells?

Question

just to clarify:

so an element has one electron shell right?

and that electron shell has sublevels

so like in the Bohr model when they have circles around the nucleus.. each circle is an orbital which is different from a shell because a shell refers to all of the orbitals??

and those circles start from s and end at f at most?

can anyone clarify all this

Answer 1

The reference gives a good overview, with diagrams. While the electron does orbit the nucleus like the earth orbits the sun, quantum physics demands that the orbits have discrete path lengths, thus the shells. Also, quantum uncertainty means the orbit is better visualized as a probability distribution 'cloud'.

Answer 2

Absolutely NOT! Each element has as many "shells" as it needs for the number of electrons it has. Each row of the Periodic Table represents another shell that is needed for all the electrons. Each shell can have multiple sub-shells, or sublevels, which have two or more orbitals. Then it gets into all kinds of crazy Quantum Mechanical reasons as to why they can only hold so many, but each shell can only hold a total of 2n^2 electrons. n is the quantum number, that corresponds to the row of the periodic table.

Hydrogen and Helium only have one shell, because once you hit two electrons, the first shell is filled. Starting with Lithium, atoms have another shell until it fills up with 8 (total of 10 electrons) for Neon.

Example: Indium, element 49 has 5 shells because it is on row 5. However, each shell has sub-shells or orbitals. Its full electron shell configuration is written in increasing levels of energy as:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p1
The first number is the shell, or periodic table row, the letters s, p, d, f and g indicate the sub-orbital, and the last number is the number of electrons in that orbital.

If you think this is confusing, you're right. Imagine the guys who had to figure this all out, back in the days when computers did not exist! All they had was paper, pencil, and plenty of midnight oil to burn....