Orbital Notation & Electron Configuration GPS Standards: SC3. Students will use the modern atomic theory to explain the characteristics of atoms. b. Use the orbital configuration of neutral atoms to explain its effect on the atom’s chemical properties 8/30/12

the boxes are in order of increasing energy for each sublevel. orbital notation = a way of showing which orbitals an atom’s electrons are spinning in. the boxes are in order of increasing energy for each sublevel. All “s” sublevels hold a total of 2 electrons. All “p” sublevels hold a total of 6 electrons. All “d” sublevels hold a total of 10 electrons. All “f” sublevels hold a total of 14 electrons. remember: The Aufbau Principle states that an electron will occupy the lowest-energy orbital that can receive it (start from the left, don’t skip any boxes). Hund’s Rule states that all same-energy orbitals must be filled by 1 electron each before any electron can pair up within an orbital (like kids on a bus).   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 1s

therefore, in order to fill an orbital notation diagram, all you have to do is fill in the boxes (from the beginning) with electrons (2 in each box) until you run out of electrons. By seeing where your last few electrons lie, you will be able to predict the chemical properties of that element. Let’s practice: Al = S = Rh = Dy = counting out electrons can get a little cumbersome when you have a lot of electrons to count, but there is an easier way!   1s 2s 2p 3s 3p   1s 2s 2p 3s 3p   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f

Sublevels found on the Periodic Table use this diagram to determine the sublevel your last few electrons are spinning in. locate your element on the PT count elements from the left- hand side of the sublevel block until you reach your element draw that number of electrons in the sublevel for your element fill in all boxes that came before the last sublevel with 2 e- each. Nd = Sr = Sb = 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 5d 6p 7s 6d 4f 5f Sublevels found on the Periodic Table   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f

Electron Configuration is very similar to orbital notation Electron Configuration is very similar to orbital notation. Both show the position of all the electrons within the atoms of an element. electron configuration = a shorter form of ON, using superscripts (instead of boxes and arrows) to show how many electrons occupy each sublevel. Adding the superscripts = the total number of e-. Below is the general order for EC: 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d10 notice how the general order above is in the exact same order you would get if you “read” the periodic table from left to right (see PT sublevel diagram). Let’s practice: Al = ___________________ Mo = ____________________________ Bi = _____________________________________________ Er = ________________________________________________

1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d10 Let’s practice: Al = ___________________ Mo = ____________________________________ Bi = _____________________________________________ Er = ________________________________________________ 1s22s22p63s23p 1 1s22s22p63s23p64s23d104p65s24d 4 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p 3 1s22s22p63s23p64s23d104p65s24d105p66s24f 12 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 5d 6p 7s 6d 4f 5f

there is another way to write the EC of an element—Noble Gas EC. the noble gases are the elements located in the last column on the PT. because of their position, they are the only elements whose last energy level is “full” (i.e. Ne has full 2s and 2p sublevels, for a total of 8 e-). we can use this information about the noble gases to shorten our EC. noble gas electron configuration = a short-hand form of EC using a noble gas symbol in brackets. Here’s how do you do it: locate your element on the PT, then look for the noble gas whose atomic number is closest to your element’s atomic number without going over. Write this noble gases’ symbol in brackets. the portion of the EC that the noble gas represents no longer has to be written, only what comes after it. 2 He 10 Ne 18 Ar 36 Kr 54 Xe 86 Rn

this is the portion of the EC represented by Kr because Kr ends in 4p6 the portion of the EC that the noble gas represents no longer has to be written, only what comes after it. example: EC and noble gas EC for tin (Sn): EC = 1s22s22p63s23p64s23d104p6 5s24d105p2 noble gas EC = [Kr]5s24d105p2 Let’s practice: Al = [___]____________ 5. Re = [___]____________ Mo = [___]____________ 6. K = [___]____________ Bi = [___]____________ 7. Cl = [___]____________ Er = [___]____________ 8. Pr = [___]____________ Now you’re ready for.... you guessed it..... a FUNSHEET!!! this is the portion of the EC represented by Kr because Kr ends in 4p6 Ne 3s23p1 Xe 6s2 4f14 5d5 Kr 5s24d4 Ar 4s1 Xe 6s24f145d106p3 Ne 3s2 3p5 Xe 6s24f12 Xe 6s2 4f3