1. Practice: Write in shorthand and noble gas notation for: F, K, Co, Kr, Ce

2. Classifying Elements by Electron Configuration

3. Classifying Elements by Electron Configuration
Blocks on the periodic table - (s,p,d,f)
Group number equals the number of electrons in the outermost energy level

4. Classifying Elements by Electron Configuration
Each period number corresponds to the outermost principle energy level

6. Practice: Identify the block (s,p,d,f) of the periodic table that this element is located. A) Zinc B) Sodium C) Uranium D) Nitrogen

7. Periodic Trends
There are 5 trends (patterns in groups or periods) on the periodic table to consider: atomic size, ionization energy, ionic size, electronegativity, and electron affinity. Read the descriptions in the notes and then answer the questions on the worksheet.

8. Trend #1: Atomic Size
Measured by the radius of an atom via x-ray diffraction

9. Trend #1: Atomic Size - below is a graph of periodic table showing atomic size trends down a group and across a period

10. Trends in Atomic Size
Atomic size increases down a group because electrons are added to higher energy levels, which are further away from the nucleus. Since there is less of an attraction of the nucleus for the electrons, the atom is larger.

11. Trend #1: Atomic Size
Atomic size decreases across a period because within the same energy level, each element has one more p+ and e- than the preceding element. Therefore, outmost e’s are attracted more closely to the nucleus making it smaller.

12. Ion
Define ion
Predict the charge of the ion typically formed by the elements in groups 1-8 on the periodic table

13. Trend #2: Ionization Energy (IE)
IE is the energy required to overcome attraction of nuclear charge and remove an electron from an atom.

14. Trend #2: Ionization Energy -graph of IE versus atomic number

15. Trend #2: Ionization Energy -graph of IE in groups and periods on the periodic table

16. Trend #2: Ionization Energy

17. Trend #2: Ionization Energy
IE decreases as you move down a group because the outermost electron is not as attracted to the nucleus so it is easier to remove

18. Trend #2: Ionization Energy
IE increases as you move left to right across a period because more protons in the nucleus lead to greater attraction for the electrons in the same energy level

19. Trend #3: Ionic Size
Cations < Neutral < Anions
Consider the attraction of the nucleus for the outermost electrons to see why this is true

20. Trend #3: Ionic Size - table of ionic size and atomic size

21. Trend #3: Ionic Size
Ionic size increases down a group because the electrons are in energy levels further away from the nucleus

22. Trend #3: Ionic Size
Across a period ionic size of positive ions and negative ions decreases
But keep in mind that anions have bigger radii than cations.

23. Trend #4: Electronegativity (EN)
EN is a measure of the ability of an atom in a chemical compound to attract electrons
Measured by the Pauling electronegativity scale.

24. Trend #4: Electronegativity - graph of electronegativity down groups and across periods of periodic table

25. Trend #4: Electronegativity
EN generally decreases down a group
EN generally increases across a period

26. Trend #5: Electron Affinity (EA)
EA is the energy change that occurs when an electron is gained by a neutral atom

27. Trend #5: Electrons Affinity
This number is negative when energy is released and positive when energy is gained

28. Trends in Electrons Affinity
EA decreases down a group
EA increases across a period

29. Review
Write the electron configuration for Sulfur in orbital, shorthand, and noble gas notation.

30. Review
Write the electron configuration for Chromium in orbital, shorthand, and noble gas notation.

31. Explain why a Mg atom is smaller than both Ca and Na atoms.
Review
Explain why a Mg atom is smaller than both Ca and Na atoms.

32. Review
Explain why a K atom has a smaller ionization energy than both Ca and Li atoms.

33. Review
The two ions K+ and Ca2+ each have 18 e-. Which would you expect to have a smaller radius? Justify your answer.

34. Review
Atomic size F Br
IE F Br
Ionic Size F Br
EN F Br
EA F Br

35. Review
Atomic size Cs Ba
IE Cs Ba
Ionic Size Cs Ba
EN Cs Ba
EA Cs Ba