1. 1 Parts 03 Periodic Trends

2. 2 1.Periodic Trends a.Atomic Radius -distance from the nucleus to the last energy level -measured in pm Li 3 7 3 p + 4 n o 2 e - 1 e - 1st 2nd atomic radius

3. 3 Li 1 e - Fr 1 e - As atomic number increases, down a group, atomic radius increases. The increased charge of the nucleus pulling in the energy levels is not enough to overcome the increasing size caused by the added energy levels. atomic radius

4. 4 Li 1e - Ne 8e - As atomic number increases across a period, atomic radius decreases. Because the number of energy levels does not increase, the increased charge of the nucleus pulling in the energy levels causes the energy levels to move closer to the nucleus and the atomic radius decreases. atomic radius

5. 5 1 2 3 4 5 7 1 2 3 4 5 7 6 7 66 a.Atomic Radius Down a group, atomic radius increases. Across a period, atomic radius decrease.

6. 6 1.Periodic Trends b.Formation of Ions -an ion is a charged particle -a cation is a positively charged particle -metal atoms form cations by losing e’ -a cation is always smaller than its atom -an anion is a negatively charged particle -nonmetal atoms form anions gaining e’ -an anion is always larger than its atom

7. 7 11 23 Na 1e - 11 p+ 12 n o 2e - 8e - Sodium Atom 11 + 11- 0 Neutral: no net charge 0 Loses its one valence electron to get a stable octet 11 23 Na 11 p+ 12 n o 2e - 8e - 11 + 10- 1+ Cation: Positively charged 1+ Sodium Ion

8. 8 Alkali Metals (group I) Very reactive! Reacts with water to form hydrogen and a base. So reactive, they are not found as an atom in nature. Reactivity increases down the group. Only found in compounds. Stored under oil due to possibility of reacting with water in the air. Alkaline Earth Metals (group II) Similar to group I. Less reactive. Not as soft. Denser. Carbon group (group IV) Can give or take 4 e -. Carbon can exist in two different physical forms. When elements can do this the forms are called ALLOTROPES. What are the two forms of Carbon? Diamond and graphite Oxygen can exist as O 2 and O 3. O 3 is called?Ozone Halogen group (group VII) Most reactive nonmetals with F being the most reactive element. They Lose one e - to gain a stable octet. Noble gases (group VIII) Chemically stable (inert). All are undetectable by human senses.

9. 9 12 24 Mg 2e - 12 p+ 12 n o 2e - 8e - Magnesium Atom 12 + 12- 0 Neutral: no net charge 0 Loses its two valence electrons to get a stable octet 12 24 Mg 12 p+ 12 n o 2e - 8e - 12 + 10- 2+ Cation: Positively charged 2+ Magnesium Ion

10. 10 13 27 Al 3e - 13 p+ 14 n o 2e - 8e - Aluminum Atom 13 + 13- 0 Neutral: no net charge 0 Loses its three valence electrons to get a stable octet 13 27 Al 13 p+ 14 n o 2e - 8e - 13 + 10- 3+ Aluminum Ion Cation: Positively charged

11. 11 15 31 P 5e - 15 p+ 16 n o 2e - 8e - Phosphorus Atom 15 + 15- 0 Neutral: no net charge 0 Gains three electrons to get a stable octet Anion: Negatively charged 15 31 P 15 p+ 16 n o 2e - 8e - 15 + 18- 3- Phosphide Ion 3-

12. 12 16 32 S 6e - 16 p+ 16 n o 2e - 8e - Sulfur Atom 16 + 16- 0 Neutral: no net charge 0 Gains two electrons to get a stable octet Anion: Negatively charged 16 32 S 16 p+ 16 n o 2e - 8e - 16 + 18- 2- Sulfide Ion 2-

13. 13 17 35 Cl 7e - 17 p+ 18 n o 2e - 8e - Chlorine Atom 17 + 17- 0 Neutral: no net charge 0 Gains one electron to get a stable octet Anion: Negatively charged 17 35 Cl 17 p+ 18 n o 2e - 8e - 17 + 18- 1- Chloride Ion 1-

14. 14 1 2 3 4 5 7 1 2 3 4 5 7 6 7 66 b.Oxidation Numbers: Charges of Ions 1+2+ Variable Oxidation Numbers Usually 2+ 3+4+4+ - 3-2-1- 0 2+ 1+ 2+ or 4+

15. 15 c.Ionization Energy Energy needed to remove one electron from the element in its isolated gaseous state X(g)+1 e - IEX 1+ (g)+ Rb(g)+1 e - IERb 1+ (g)+

16. 16 16 32 S 6e - 16 p+ 16 n o 2e - 8e - Sulfur Atom 16 + 16- 0 Neutral: no net charge 0 Ionization Energy removes one electron from the last energy level 16 32 S 16 p+ 16 n o 2e - 8e - 5e - 16 + 15- 1+ Positive Ion 1+

17. 17 1 2 3 4 5 7 1 2 3 4 5 7 6 7 66 c.Ionization Energy Down a group, ionization energy decreases. The atoms get larger so it is easier to remove 1e -. Across a period, ionization energy increases. The atoms get smaller so it is more difficult to remove 1e -.

18. 18 Examples: What element has the smallest atomic radius in group II? Beryllium What element has the largest ionization energy in group VI? Oxygen

19. 19 Examples: What element has the largest atomic radius in Period 4? Potassium What element has the highest ionization energy in Period 5? Xe

20. 20 Examples: What is the oxidation number of radium? 2+ What is the oxidation number of selenium? 2- What is the oxidation number of gallium? 3+ What is the oxidation number of iodine? 1- Assignment p.58-68… p. 69-70 will be extra credit on the test.