Lecture23221

Slide 1: The Periodic Table: Principles of Electron Configuration Lecture 23

Slide 2: Elements in a group have similar chemical properties because they have similar outer electron configurations.

Slide 3: Three categories of electrons: Inner (core) electrons – those seen in the previous noble gas. Outer electrons – those in the highest energy level. Valence electrons – those involved in forming compounds.

Slide 4: Key information embedded in the periodic table: The group number equals the number of outer electrons. The period number is the n value of the highest energy level. The n value squared (n2) gives the total number of orbitals in that energy level. The 2n2 value gives the maximum number of electrons in the energy level.

Slide 5: A sample problem on determining electron configurations of given elements.

Slide 6: Orbitals are filled in order of increasing energy, which leads to outer electron configurations that recur periodically, which leads to chemical properties that recur periodically.

Slide 7: How the orbitals are filled:

Slide 8: A sample inverted problem on determining elements by their electron configurations.

Slide 9: How the orbitals are filled:

Slide 10: What is this? 1s22s22p63s23p64s1 1s2 – 2s22p6 – 3s23p6 – 4s1 [He] – [Ne] – [Ar] – 4s1 It is potassium!

Slide 11: What is this? 1s22s22p63s23p64s23d104p65s24d9 1s2 – 2s22p6 – 3s23p6 – 4s23d104p6 – 5s24d9 [He] – [Ne] – [Ar] – [Kr] – 5s14d8 It is ruthenium!

Slide 12: THE END