1. Bell Work Write the Electron Configuration for Potassium: 1s 2s 2p 3s 3p 4s 3d Argon: 1s 2s 2p 3s 3p 4s 3d Then Circle the Valence Electrons

2. Periodic Trends Ionization Energy Atomic Radius Electron Affinity Electronegativity

3. Objectives: Compare period and group trends. Relate period and group trends in atomic radii to electron configuration

4. Background Electrons can jump between shells/orbitals The electrons can be pushed so far that they escape the attraction of the nucleus Losing an electron is called ionization An ion is an atom that has either a net positive or net negative charge Gaining an electron is electron affinity

5. What are Periodic Trends? Trends among elements in the periodic table. Example: Atomic Radius(size) Ionization Energy Electronegativity Electron Affinity

6. What is Atomic Radius? Half the distance between adjacent nuclei

7. Decrease in atomic radius as you move left to right on the periodic table: Valence electrons are pulled closer to the nucleus Increase in atomic radius as you go down a group on the periodic table: Radius increases because shells are added because of more electrons What are the atomic radius trends?

8. Which Atom has the bigger atomic radius? Carbon or Fluorine Answer: Carbon Carbon or Tin Answer: Tin

9. What is Ionization energy? Ionization energy is the energy required to remove one outer electron from an atom 11p + 12n ° Loses an electron Na Atom Na Ion

10. Increases a you move from left to right. More protons means greater attraction between nucleus and outer electron thus higher ionization energy. Li ( 1) + + + Be ( 2) + + + + B ( 3) + + + + + What are the periodic trends for Ionization Energy?

11. Decreases a you move down a group. Radius increases because shells are added. Increased radius will make it easier to lose an electron because of greater distance between positive and negative charges What are the periodic trends for Ionization Energy? (Continued)

12. Which Atom has the greater Ionization Energy? Boron or Aluminum Answer: Boron Sodium or Magnesium Answer: Magnesium

13. Electron affinity is energy associated with an atom gaining an electron. Electronegativity is a number that describes the relative ability of an atom to attract electrons. What is Electronegativity… Electron Affinity?

14. It is highest in the top right where atoms are smallest with the greatest number of protons (Electron Affinity) The trend is the same as affinity for the same reason (Electonegativity) What are the trends for Electronegativity… Electron Affinity?

15. Electronegativity

16. Which Atom has the greatest Electronegativity? Fluorine

17. Homework Periodic Trends Engrade.com

18. Classwork Graphing Periodic Trends(periods 1, 2, 3) Connect the points of elements in each period, so that there are 3 separate curves (use 3 different colors on the graphs). Atomic Radius: Y- Axis Atomic Number: X-Axis

19. Thought For the Week! Does thou love life….Do not squander time, because that is the stuff life is made of. Benjamin Franklin