1. Chapter 13.1-13.2

2.  Orbitals are three dimensional regions around the nucleus that indicate the probable location of an electron.  Only two electrons can fit in an orbital.

3.  Principal energy levels are broken into sublevels.  Sublevels are made of one or more orbital. There are four different types of sublevels – and each has a different shape and maximum number of electrons that it can hold.

4.  s sublevel orbitals are spherical  In a given energy level, s sublevels have the lowest amount of energy  There is only one orbital in a s sublevel so … only two electrons can fit in an s sublevel Most of the time, the electrons are located within this area.

5.  p sublevels contain the second type of orbital in a given energy level  There are three dumbbell shaped orbitals in a p sublevel so … six electrons can fit in a p sublevel

6.  d sublevels are comprised of the third type of orbital in a given energy level  There are five orbitals in a d sublevel so … ten electrons can fit in a d sublevel There are 4 clover shaped orbitals And then there is one shaped like a dumbbell with a hula-hoop!

7.  f sublevels are comprised of the fourth type of orbital in a given energy level  There are seven orbitals in an f sublevel so … fourteen electrons can fit in an f sublevel

8. Sublevel TypeNumber of Orbitals Maximum Number of Electrons s12 p36 d510 f714

9.  This states that electrons fill the energy levels that are lowest energy first.

10. 1s 2 2p 6 3s 2 2s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 2 1 2 3 4 5 67 1s 2s2p 3s3p3d 4s4p4d4f 5s5p5d5f 6s6p6d6f 7s7p7d7f

11.  For two electrons to occupy the same orbital, they must have an opposite spin.

12.  Orbitals of equal energy (within the same sublevel) must each be occupied by one electron with the same spin before any electrons may share the orbital.

13.  Each electron in an atom has four quantum numbers which describe its location and energy within the atom. Quantum Number Type DescriptionExplanation nPrincipal energy level SIZE of the orbital lSublevelSHAPE of the orbital mOrbital within the sublevel ORIENTATION of the orbital (in 3-D space) sSpin of electrons SPIN of the electron

14.  This is accomplished in three different ways  Orbital Notation  Electron Configuration Notation  Noble Gas Notation

15.  Orbital notation expresses the energy level, sublevel, and spin of the electrons involved.  An unoccupied orbital is shown as  Each electron is represented as an arrow  The direction of the arrow represents the spin of the electron.

16.  Problem: Write the orbital notation for carbon.  Step 1: Determine the number of electrons in one atom of carbon Answer – 6 electrons total  Step 2: Fill the sublevels, starting with the lowest to highest energy. Be sure to have 2 e - with opposite spin in each orbital involved. 1s 2s 2p

17.  Problem: Write the orbital notation for sodium.  Step 1: Determine the number of electrons in one atom of sodium Answer – 11 electrons total 1s 2s 2p 3s

18.  Electron configuration notation does not account for the spin of electrons.  It only addresses the energy level, sublevel type, and number of electrons in a given sublevel.

19.  Problem: Write the electron configuration for silicon.  Step 1: Determine the number of electrons in one atom of silicon. Answer – 14 electrons total  Step 2: Fill the sublevels in order according to the Aufbau principle. 1s 2 2s 2 2p 6 3s 2 3p 2

20. YES! A SHORTCUT!! The noble gases are comprised of the column on the right side of the periodic table. They represent full sublevels, so they can be used as an abbreviation within a given electron configuration. To use this shortcut, you must identify the noble gas which comes immediately before a given element on the periodic table. Then, you only need to write the configuration for the electrons which are additional to those within the noble gas.

21.  Previously, we had written the electron configuration for silicon.  You can use neon as a shortcut. Write its symbol in brackets, and then continue with the rest of the configuration This part of the configuration corresponds to the element Neon 1s 2 2s 2 2p 6 3s 2 3p 2 [Ne]

22.  Write the full electron configuration for Chlorine. Then write the noble gas shortcut. 1s 2 2s 2 2p 6 3s 2 3p 5 [Ne] 3s 2 3p 5