Catalyst

1. Catalyst Use your notes to answer the following questions • 1. What group is Br in? • 2. What family is Br in? • 3. What family is Mg in? • 4. Is Cl a metal or a nonmetal? • 5. What period is Ne in?

3. BY THE END OF TODAY • You should be able to answer this question: • Beryllium (Be) has a ______ atomic size and a ______ electronegativity compared to Nitrogen (N). • A. larger; larger B. larger; smaller • C. smaller; smaller D. smaller; larger

4. Today’s Agenda

5. What is a trend? • Is the average senior shorter or taller than the average freshman? • So are older students generally taller or shorter than younger students? • We would say that there is a trend: as grade level increases, height increases. • What are some other trends?

6. What is Atomic Size? • Atomic size is… • How big an atom is • Also known as atomic radius

7. Na H K Li Fr Rb Cs

8. WHAT DID YOU NOTICE? • What is happening in this graph? • The atomic size is increasing as you move down a group

9. Li Be B F N O Ne C

10. WHAT DID YOU NOTICE? • What is happening in this graph? • The atomic size is decreasing as you move across a period

11. PUT IT TOGETHER! • Atomic size (radius) increases as you move down a group, and decreases as you move left to right across a period

13. Why? • Why do elements get smaller as we go to the right? • More protons, pulls in those electrons closer.

14. Why do elements get bigger as you go down the group? More electrons block the positive charge of the nucleus on the outer electrons. This is called electron shielding.

15. Practice Problems: Level 1 • Write and answer these in your notes • 1. Which of the following has the largest atomic radius? C, F, Be, Ne • 2. Which of the following has the smallest atomic radius? Ge, Pb, Sn, C

16. Practice Problems Method Which of the following has the largest atomic radius? C, F, Be, Ne Method: • Question Asking? ___________________ • Horizontal or Vertical Trend? ___________________ • “Biggest” or “Smallest”? __________________ • Direction of Arrow? ______________________ • Answer ________________________ Atomic Radius Horizontal Biggest Left Be

17. Practice Problems Level 1 • Answer these in your notes • 1. Which of the following has the largest atomic radius? C, F, Be, Ne • 2. Which of the following has the smallest atomic radius? Ge, Pb, Sn, C

18. Practice Problems Method Which of the following has the smallest atomic radius? Ge, Pb, Sn, C Method: • Question Asking? ___________________ • Horizontal or Vertical Trend? ___________________ • “Biggest” or “Smallest”? __________________ • Direction of Arrow? ______________________ • Answer ________________________ Atomic Radius Vertical Smallest Up C

19. Practice Problems Level 1 • Answer these in your notes • 1. Which of the following has the largest atomic radius? C, F, Be, Ne • 2. Which of the following has the smallest atomic radius? Ge, Pb, Sn, C

20. Practice Problems Level 2 • Write and answer in your notes • Rank the following elements in order of increasing atomic size based on location on the periodic table (smallest to biggest) • Fr, W, P, Ga P, Ga, W, Fr F, As, Tl, S F, S, As, Tl

21. Today’s Agenda

22. What is electronegativity? • Electronegativityis… • The ability of an atom to attract electrons to itself in a chemical bond • How much an atom wants electrons

23. H Li Na K Rb Fr Cs

24. WHAT DO YOU NOTICE? • What is happening in this graph? • The electronegativity is decreasing as you move down a group

25. Li B O F N Be C

26. WHAT DO YOU NOTICE? • What is happening in this graph? • The electronegativity is increasing as you move left to right across a period

27. PUT IT TOGETHER! • Electronegativity decreases as you move down a group, and increases as you move left to right across a period

28. Electronegativity Trends

29. Practice Problems: Level 1 • Write and answer these in your notes • 1. Which of the following has the largest electronegativity? C, F, Be, Ne • 2. Which of the following has the smallest electronegativity? Ge, Pb, Sn, C

30. Practice Problems Method Which of the following has the largest electronegativity? C, F, Be, Ne Method: • Question Asking? ___________________ • Horizontal or Vertical Trend? ___________________ • “Biggest” or “Smallest”? __________________ • Direction of Arrow? ______________________ • Answer ________________________ Electronegativity Horizontal Biggest Right Ne

31. Practice Problems: Level 1 • Write and answer these in your notes • 1. Which of the following has the largest electronegativity? C, F, Be, Ne • 2. Which of the following has the smallest electronegativity? Ge, Pb, Sn, C

32. Practice Problems Method Which of the following has the smallest electronegativity? Ge, Pb, Sn, C Method: • Question Asking? ___________________ • Horizontal or Vertical Trend? ___________________ • “Biggest” or “Smallest”? __________________ • Direction of Arrow? ______________________ • Answer ________________________ Electronegativity Vertical Smallest Down Pb

33. Practice Problems Level 1 • Answer these in your notes • 1. Which of the following has the largest atomic radius? C, F, Be, Ne • 2. Which of the following has the smallest atomic radius? Ge, Pb, Sn, C

34. Practice Problems Level 2 • Write and answer in your notes. • Rank the following elements in order of increasing electronegativity based on location on the periodic table (smallest to biggest) • Mg, Sr, Be, Ra Ra, Sr, Mg, Be Cl, Si, Al, S, P Al, Si, P, S, Cl

35. How is atomic size related to electronegativity? Atomic size is indirectly related to electronegativity. (They are opposites.) ATOMIC SIZE As electronegativity increases, atomic size decreases! ELECTRONEGATIVITY

36. Why is this relationship true? • Atoms with HIGH ELECTRONEGATIVITIES hold their electrons very close! • So, the atomic size decreases High or low electronegativity? Large or small atomic size?

37. Practice Problem Level 3 • Chlorine (Cl) has a ______ atomic size and a ______ electronegativity compared to Oxygen (O). • A. larger; larger B. larger; smaller • C. smaller; smaller D. smaller; larger

38. Today’s Agenda

39. Exit Slip • 1. What element has the largest atomic radius? • Flourine • Hydrogen • Radon d.Caesium 2. What element has the largest electronegativity? • Flourine • Hydrogen • Radon d.Caesium

40. Exit Slip 3. True or false: Electronegativity is an atom’s ability to repel electrons. 4. Flourine(F) has a ______ atomic size compared to Oxygen (O). • Larger • Smaller • Equal 5. Chlorine (Cl) has a _______ electronegativity compared to Aluminum (Al). • Larger • Smaller • Equal

41. Independent Practice Classwork: Answer these 5 questions independently in your notes (10min) You do not have to write the question. • 1. True or false: Electronegativity is an atoms ability to repel electrons. (If false, why is this false?) • 2. Order the following elements in order of decreasing electronegativity: Y, Ti, Sg, Ta • 3. Order the following elements in order of increasing atomic size: Sb, I, Ag, Ru • 4. Rank the following elements in order of decreasing atomic size: Rb, K, Sr, Ca • 5. As electronegativity increases, what happens to atomic size? Explain why using words and a picture.