1. Periodic Trends

2. The Periodic Law When arranged by increasing atomic number, the chemical elements display a regular and repeating pattern of chemical and physical properties. Atoms with similar properties appear in groups or families (vertical columns) They are similar because they all have the same number of valence (outer shell) electrons

3. The Periodic table Prentice-Hall © 2002General Chemistry: Chapter 10Slide 3 of 35 Alkali MetalsAlkaline EarthsTransition MetalsHalogensNoble Gases Lanthanides and Actinides

4. The Octet Rule The “goal” of most atoms is to have an octet or group of 8 electrons in their valence energy level. They may accomplish this by either giving electrons away or taking them. Atoms that have gained or lost electrons are called ions. Ions When an atom gains an electron, it becomes negatively charged (more electrons than protons ) and is called an anion. When atoms lose electrons they become positively charged cations.

5. Oxidation Numbers: The charge that will occur when an element gains or loses an electron in the predicted way

6. Atomic Radius = the distance from the center of the nucleus to the “edge” of the electron cloud.

7. Ionization Energy = The energy required to remove an electron from an atom. The larger the atom is, the easier its electrons are to remove. Ionization energy and atomic radius are inversely proportional.

8. Electronegativity = a measure of an atom’s attraction for another atom’s electrons. --Generally, metals give electrons away and have low electronegativities. --Nonmetals take electrons from other atoms and have high electronegativities. 0

9. Electron Configurations can be Determined From the Position in the Periodic Table: Elements in group 1(1A) end in ns 1. Elements in group 2 (2A): end in ns 2 Elements in group 13 (3A) end in ns 2 np 1 Elements in group 14 (4A): end in ns 2 np 2 Elements in group 15 (5A) end in ns 2 np 3 Elements in group 16 (6A) end in ns 2 np 4 Elements in group 17 (7A) end in ns 2 np 5 Elements in group 18 (8A) end in ns 2 np 6

10. 1s11s1 1s 2 2s 1 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 1 H 1 Li 3 Na 11 K 19 Rb 37 Cs 55 Fr 87 Do you notice any similarity in these configurations of the alkali metals?

11. He 2 Ne 10 Ar 18 Kr 36 Xe 54 Rn 86 1s21s2 1s 2 2s 2 2p 6 1s 2 2s 2 2p 6 3s 2 3p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 Do you notice any similarity in the configurations of the noble gases?

12. Elements in the s - blocks Alkali metals all end in s 1 Alkaline earth metals all end in s 2 really should include He, but it fits better in a different spot, since He has the properties of the noble gases, and has a full outer level of electrons. s2s2 s1s1 He

13. Transition Metals - d block d1d1 d2d2 d3d3 s1d5s1d5 d5d5 d6d6 d7d7 d8d8 s 1 d 10 d 10 Note the change in configuration.

14. The P-block p1p1 p2p2 p3p3 p4p4 p5p5 p6p6

15. F - block Called the “inner transition elements”

16. Each row (or period) is the energy level for s and p orbitals. 12345671234567 Period Number

17. The “d” orbitals fill up in levels 1 less than the period number, so the first d is 3d even though it’s in row 4. 12345671234567 3d 4d 5d

18. f orbitals start filling at 4f, and are 2 less than the period number 12345671234567 4f 5f

19. The Aufbau Principle Each electron occupies the lowest energy orbital i.e. Electrons are Lazy! All orbitals related to an energy level are of equal energy. i.e. The three 2p orbitals are the same energy level.

20. Hund’s Rule Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals. i.e. Electrons are unfriendly!

21. Pauli Exclusion Principle A maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins. Spin -- Electrons have an associated “spin,” either one way or the other, like a top. These spins are called “spin up” and “spin down.” Exceptions to filling order are copper, chromium and some others- because half-filled shells are more stable, so an atom may borrow an electron from next s shell to half fill a lower energy level.