Dec 212009
I have a research project on the element cobalt. I have read its a transition metal and when i look this up it, its defined as “an element whose atom has an incomplete d sub-shell”. What does this mean? Please explain what an incomplete d sub-shell means or if you can, try to explain what a transition metal is.
The transition metals fall in the center of th periodic table. They have more than one oxidation number. They form colored compounds.
Well, a d sub-shell has a max of 10 electrons if there are less it’s, incomplete. A sub-shell is one of the sets of electrons orbiting an element at a particular energy level (distance). If the d sub-shell has less than 10 electrons it’s a transition metal, the simple way to say it is literally that it’s not quite a metal and not quite a gas. It lives somewhere in between like mercury. Though technically mercury is not a transition metal, while cobalt is, why? One of its particular electron orbits is should have 10 but does not, the “d sub-shell”.
if someone is talking about a transition metal in general, they are talking about the middle section of the periodic table, so the ‘B’ collumns.
these elements are special because of the arrangement of electrons around the nucleushttp://boomeria.org/chemlectures/ch9orbi…
that link is a picture. each orbital can have only 2 elctrons in it. so, the more electrons an element has, the more orbitals are available. electrons must fill the orbitals in a specific order, but there are some exceptions that kind of cheat that rule.
hydrogen has only 1 electron, and helium has 2. hydrogen has a 1s electron orbital, and so does helium, but helium completely fills the 1s orbital. one row down you graduate to 2s electron orbital. and except for helium, all of the elements on the right side of the periodic table make it all the way up to ‘p’ electron orbitals. and the transition metals go up to ‘d’ level, and the two rows underneath on their own go all the way up to the max of ‘f’ orbitals. don’t ask where the letters come from…
anyway, each shell is filled one two, one two, one two, except where the d orbitals are concerned. they fill in this order because it takes the least amount of energy to do it, and we all know that nature is as lazy as it can be, right? well, the d orbitals can actually cheat and fill in a different order because it actually takes less energy.
this is probably way more detail than you wanted, so i’m going to leave it at that because this is college sophmore level chemistry.