1. WARMUP Discuss with your table partner:
What trends did you see in the Mendeleev activity we did last class?
What did you notice about melting points, colors, densities, hardness, and reactivity within a group and going down a group?
If you didn’t finish the questions for the Mendeleev activity, get them done now so you can turn it in.
We will be taking notes today, so make sure to get your notebook.

2. We will learn about periodic trends.
I will complete a periodic trends worksheet.
Success Criteria
Know the trends in atomic radius, ionic radius, electronegativity, and ionization energy across the periodic table.

3. Housekeeping
We will have another test next week over periodic table trends and families. Expect to see some of the most-missed questions from the last test come back again.
All work from the last unit needs to be turned in by Friday THIS WEEK in order to receive any credit. This means electron configuration lab, History of the Periodic Table, and Periodic Table Packet.
Test will be passed back today. You have until Thursday next week to complete corrections and retest (if needed).

4. Pass back test and go over it
An atom has the electron configuration 1s22s22p63s23p5. The dot diagram for this element is
What is the total number of valence electrons in an atom with the electron configuration 1s22s22p63s23p3?
3. Which atom in the ground state has three unpaired electrons in its outermost principal energy level? (period 2)
In the second energy level, which sublevels are possible?

5. 5. How many orbitals are in the d sublevel?
What is the maximum number of electrons the third energy level can hold?
7. Which of the following is the correct electron configuration for an ion of silicon with a +4 charge?
Identify the element with the noble gas configuration [Kr]5s24d105p2

6. 9. Which of the following negative ions would have the same electron configuration as an atom of neon?
10. Identify the correct orbital diagram for an atom of nitrogen in the ground state.
11. Henry Mosely’s periodic table was an improvement to the periodic table designed by Mendeleev because Mosely’s table ___________________.
12. Using his periodic table, Mendeleev was able to _____________________.

7. 13. An element that will conduct heat and electricity is ______.
Iron b. Carbon c. chlorine d. Nitrogen
14. The first element in a period is always a ________________.
15. Neon is a noble gas. Which of the following describes neon?

8. How does an atom become an ion?

9. How were Mendeleev’s and Mosely’s tables different?

10. Electron Configuration
Symbol
Atomic Number
Proton Number
Mass Number
Neutron Number
Electron Configuration
(2points each)
Dot Diagram 32 13 14

11. Electron Configuration
Symbol
Atomic Number
Proton Number
Mass Number
Neutron Number
Electron Configuration
(2points each)
Dot Diagram 14 20 19

12. Orbital notation
Electron configuration
Noble Gas notation

13. 4-1-1 with a video
Don’t write any notes. Just pay attention to the video.
After the video is over, take 1 minute to write down what you thought was important.
At the end of 1 minute, share with your table partner. If you are sitting alone, then share with a table that is next to you.

15. 4-1-1
Take 1 minutes to write down on the whiteboard what you thought were the most important points. NO TALKING at this time.

16. 4-1-1 Spend one minute sharing with your table partner.
We will take notes afterward.

17. New notes section Title this section: Periodic Trends
NOTE - for atomic radius, ionic radius, ionization energy, and electronegativity, you MUST know the REASON as well as the trend.

18. Atomic Radius
How big an atom is.

19. Increase in atomic radius

20. Atomic Radius How big an atom is. Down a group - increases
BECAUSE adding new energy level makes atom bigger
Across a period - decreases
BECAUSE adding protons increases pull on e-, pulls them closer to nucleus

21. Which element has the largest atomic radius?
S Mg K O

22. Ionic Radius How big an ion is.
Cations are SMALLER than the neutral atoms they come from,
BECAUSE we have the same number of protons pulling in on a smaller number of electrons.

23. Ionic Radius How big an ion is.
Anions are LARGER than the neutral atoms they come from,
BECAUSE we have the same number of protons pulling in on a larger number of electrons.

24. Increase in ionic radius

25. Ionic Radius How big an ion is. Down a group -increases
BECAUSE valence e- are farther from nucleus
Across a period - decreases
BECAUSE valence e- are closer to nucleus

26. Which element has the largest ionic radius?
Li Ca O Rb

27. Ionization Energy
Amount of energy it takes to remove an electron (become a cation)

28. Increase in ionization energy

29. Ionization Energy
Amount of energy it takes to remove an electron (become a cation)
Down a group - decreases
BECAUSE valence e- are far from nucleus and easy to remove
Across a period - increases
BECAUSE more protons pull harder on valence e- and make them harder to remove

30. Which has a higher ionization energy, metals or nonmetals? Why?

31. Electronegativity
Strength of attraction an atom has to hold onto its electrons

32. Increase in electronegativity

33. Electronegativity
Strength of attraction an atom has to hold onto electrons
Down a group - decreases force of attraction
BECAUSE valence e- are farther away from nucleus
Across a period - increases force of attraction
BECAUSE more protons have more strength to pull e-

34. Which element is the most electronegative?
S Mg K O

35. Metallic characteristics
How readily an atom can lose an electron.
Down a group - metallic characteristics increase
Across a period - metallic characteristics decrease
Metallic character relates to the ability to lose electrons, and nonmetallic character relates to the ability to gain electrons.

36. Decrease in metallic character
Increase in metallic character

37. Shielding effect
The shielding effect describes the balance between the pull of the protons on valence electrons and the repulsion forces from inner electrons.
The shielding effect explains why valence-shell electrons are more easily removed from the atom. The effect also explains atomic size. The more shielding, the further the valence shell can spread out and the bigger atoms will be.
The effective nuclear charge is the net positive charge experienced by valence electrons. It can be approximated by the equation: Zeff = Z - S, where Z is the atomic number and S is the number of shielding electrons.
Source: Boundless. “ The Shielding Effect and Effective Nuclear Charge.” Boundless Chemistry. Boundless, 08 Aug Retrieved 06 Nov from effective-nuclear-charge /

38. Pass back test and go over it
An atom has the electron configuration 1s22s22p63s23p5. The dot diagram for this element is
What is the total number of valence electrons in an atom with the electron configuration 1s22s22p63s23p3?
3. Which atom in the ground state has three unpaired electrons in its outermost principal energy level? (period 2)
In the second energy level, which sublevels are possible?

39. 5. How many orbitals are in the d sublevel?
What is the maximum number of electrons the third energy level can hold?
7. Which of the following is the correct electron configuration for an ion of silicon with a +4 charge?
Identify the element with the noble gas configuration [Kr]5s24d105p2

40. 9. Which of the following negative ions would have the same electron configuration as an atom of neon?
10. Identify the correct orbital diagram for an atom of nitrogen in the ground state.
11. Henry Mosely’s periodic table was an improvement to the periodic table designed by Mendeleev because Mosely’s table ___________________.
12. Using his periodic table, Mendeleev was able to _____________________.

41. 13. An element that will conduct heat and electricity is ______.
Iron b. Carbon c. chlorine d. Nitrogen
14. The first element in a period is always a ________________.
15. Neon is a noble gas. Which of the following describes neon?

42. How does an atom become an ion?

43. How were Mendeleev’s and Mosely’s tables different?

44. Electron Configuration
Symbol
Atomic Number
Proton Number
Mass Number
Neutron Number
Electron Configuration
(2points each)
Dot Diagram 32 13 14

45. Electron Configuration
Symbol
Atomic Number
Proton Number
Mass Number
Neutron Number
Electron Configuration
(2points each)
Dot Diagram 14 20 19

46. Orbital notation
Electron configuration
Noble Gas notation

47. Complete Periodic Trends worksheet
You have the rest of the class to complete the Periodic Trends worksheet and any missing work. You can also work on test corrections.
You may work in groups of 2 or 3.

48. HAVE A NICE DAY!
Put your notebook away. Work on any missing assignments.