1. Chemistry Periodic Trends

2. Section 5 Definitions Atomic Radius Ion Cation Anion Ionization Energy Electronegativity

3. Size Does Matter How big is an atom? ATOMIC RADIUS: measure of the size of atoms

4. In general, atomic size increases from top to bottom in a group and decreases from left to right across a period.

5. Trends in Atomic Size

6. Ionic ION: An atom or groups of atoms that has a positive or negative charge Neutral atoms (# p + = # e - ) Positive and negative ions form when electrons are transferred between atoms Metals tend to lose e -, nonmetals tend to gain e -

7. CATION: Ion with a positive charge –Form when elements LOSE electrons –# of positive and negative is now imbalanced –More positive than negative charge

8. ANION: Ion with a negative charge –Form when elements GAIN an electron –# of positive and negative is now imbalanced –More negative than positive charge

9. Elements (metals) in group 1A will lose one e - to be like the nearest noble gas –Example, Na loses one to be like Ne, which has 10 e - –Easier to lose one than gain 7 e - to be like Ar –Losing one electron throws off the balance of positive to negative, making Na + –Na does NOT become Neon though, just like it –Which noble gas does K want to be like? How would it achieve this? How would metals in group 2A behave?

10. Elements (nonmetals) in group 7A will gain one e - to be like the nearest noble gas –Example, F gains one to be like Ne, which has 10 e - –Easier to gain one than lose 7 e - to be like He –Gaining one electron throws off the balance of positive to negative, making F - –F does NOT become Neon though, just like it –Which noble gas does Cl want to be like? How would it achieve this? How would nonmetals in group 6A behave?

11. Sodium becoming like Neon

12. IONIZATION ENERGY: Energy required to remove an e - from an atom 1st ionization energy is the energy required to remove the first e - from an atom called Tends to decrease from top to bottom and increase from left to right Elements also have 2 nd, 3 rd, etc ion energy

13. Pg 173 For ionization energy table

14. Trends in Ionization Energy

15. Ionic Radius Ion of a metal is smaller than the element before it was ionized –Electron given away Ion of a nonmetal is larger than the element before it was ionized –Electron accepted

16. Trends in Ionic Radius Size generally increases

17. How Negative R U? ELECTRONEGATIVITY: The ability of an atom of an element to attract electrons when the atom is in a compound Metals have low electronegativities; want to give away e - Nonmetals have high electro.; want to gain e -

18. Page 177 Tends to decrease from top to bottom and increase from left to right –Transition metals irregular

19. Section 5 Assignment Draw a big Periodic table and draw arrows that represent the four trends we discussed. Make sure to draw your arrows in a way that shows how the trend changes. Below this large table explain what each trend means. For the following elements, determine which of the pair has the largest atomic radius, ionization energy, and electronegativity. Finally, figure out what ion each would form (what charge and how you would write that) –Li and K –Ca and Br –Cl and I –Fr and F

20. Ionization Energy and Electronegativity Values