1. Periodicity
Periodic Table Trends

2. Remember these groups of the periodic table?

3. Periodic Law
There are repeating patterns in the chemical and physical behavior of elements when organized by their atomic number.

4. Classifying Elements by Electron Configuration
e- play significant role in determining physical and chemical properties of elements
Elements are arranged by their properties
relationship b/w e- config & placement of elements in the table

5. How the configurations of the noble gases similar?
1s22s22p6
1s22s22p63s23p6
1s22s22p63s23p64s23d104p6
1s22s22p63s23p64s23d104p65s24d105p6
1s22s22p63s23p64s23d104p65s24d10 5p66s24f145d106p6 2 Ne 10
The outer energy level is completely full! Ar 18 Kr 36 Xe 54 Rn 86

6. How are the configurations of the alkali metals similar?1 Li 3 Na 11 K 19 Rb 37 Cs 55 Fr 87
1s1
1s22s1
1s22s22p63s1
1s22s22p63s23p64s1
1s22s22p63s23p64s23d104p65s1
1s22s22p63s23p64s23d104p65s24d10 5p66s1
1s22s22p63s23p64s23d104p65s24d105p66s2 4f145d106p67s1
They all end in s1

7. Every element in group 15 has what outer electron configuration?

8. Periodic Trends
These patterns in electron configurations produce patterns in properties.
These patterns are called Periodic Trends.

9. There are 5 major trends that occur in periodic table:
Atomic Mass & Atomic Number
Atomic Size
Ionic Size
Ionization Energy
Electronegativity

10. 3 factors that effect Periodic Trends
1. Nuclear Charge (# protons)
More p+ = greater charge which pulls e- closer ~ effect s period
2. Energy level
More E levels farther away the valence e-
~effects group
3. Shielding effect

11. Shielding Effect
Inner e- blocks the nuclear charge from reaching the valence e- due  E Level +

12. Atomic Mass & Atomic #
Increase from top left to bottom right

13. Atomic Size (radius)

14. Atomic Size

15. Atomic Size - Group trendsH
Going down a group, atoms add another energy level
 atoms get bigger. Li Na K Rb

16. Atomic Size - Period Trends
left to right across a period, the size gets smaller.
e- are in the same energy level but more nuclear charge
valence e- are pulled closer by inc in protons. Na Mg Al Si P S Cl Ar

17. Which atom is bigger & Why?
Li or Cs
Ga or B
O or C
Be or Ba
Si or S

18. What do you think the word Octet means?

19. Octet Rule = 8
Gain, lose, or share electrons to become STABLE like Noble gases s2p6 **Exception energy level 1

20. When atoms are trying to obey the octet rule they will…
IONS
When atoms are trying to obey the octet rule they will…

21. Atom loses electron : cation
more protons than electrons
Group
Obeys Octet Rule How
Oxidation Number
Group 1
loses 1 e- 1+
Group 2
Loses 2 e- 2+
Group 13
Loses 3e- 3+

22. Atom gained electron: anion more electrons than protons
Group
How atom obey Octet Rule
Oxidation Number
Group 15
Add 3 e-
3 -
Group 16
Add 2 e-
2 -
Group 17
Add 1e-
1 -

23. Ionic Size
Metals: Determine if their ions are smaller or bigger than the neutral atom Nonmetals:

24. Metal ION ic Size
1. Smaller
2. Lose valence electrons

25. NonMetal ION ic Size
Bigger
Gain valence electrons

26. Metal
NonMetal

27. Which ion in each, is smaller?
1. Al3+ or P3- 2. K+ or Cs+ 3. O2- or Te2-

28. Ionization Energy (1st)
Energy needed to remove ONE electron from an atom …. i.e. “How strongly can atom hold onto it’s valence electrons?”

29. Ionization Energy

30. Low Ionization Energy
Easy to steal an electron away Analogy: Easy to steal a purse away from a little old lady.

31. High Ionization Energy
Hard to steal an electron away Analogy: Hard to steal a purse away from someone muscular

32. Going Down a Group Bigger atom= less E to remove e-= lower IE
Ionization Energy Decreases….
Valence e- farther from nucleus = not held as tight by nucleus
Bigger atom= less E to remove e-= lower IE

33. Going Across a Period  Smaller atom = more E to remove e-= higher IE
Ionization Energy Increases…
1. atom smaller: e- closer to nucleus
2. closer to being a noble gas
 Smaller atom = more E to remove e-= higher IE

35. Which atom has larger (1st ) Ionization Energy ?
1. Na or S 2. Mg or Ba 3. Ga or Br 4. P or Bi

36. Arrange the following elements in order of decreasing (1st) Ionization Energy?
Cs, Li, K
Cl, Si, P
Ca, Ba, Be, Sr

37. Electronegativity: bonded elements
likelyhood to WANT to take electron from another
atom

38. Electronegativity
Like tug of war

39. Going Down a Group Distance from nucleus increases
Electronegativity Decreases…
Distance from nucleus increases
valence electrons NOT held strongly by nucleus

40. Going Across Period
Electronegativity Increases.. 1. inc attraction to nucleus 2. closer to being a noble gas  it wants an electron

42. Which atom has higher Electronegativity?
Na or Mg
K or Br
F or Br
Ca or Ga
Li or S
Br or As

43. Summary Ionization energy decreases Electronegativity decreases
Nuclear charge increases
Atomic radius increases
Shielding increases
Shielding is constant
Atomic Radius decreases
Ionization energy increases
Electronegativity increases
Nuclear charge increases

44. Ranking Elements by Atomic Size
SAMPLE PROBLEM
Ranking Elements by Atomic Size
PROBLEM:
Using only the periodic table (not Figure 8.15), rank each set of main group elements in order of decreasing atomic size:
(a) Ca, Mg, Sr
(b) K, Ga, Ca
(c) Br, Rb, Kr
(d) Sr, Ca, Rb
PLAN:
Elements in the same group increase in size and you go down; elements decrease in size as you go across a period.
SOLUTION:
These elements are in Group 2A(2).
(a) Sr > Ca > Mg
These elements are in Period 4.
(b) K > Ca > Ga
Rb has a higher energy level and is far to the left. Br is to the left of Kr.
(c) Rb > Br > Kr
Ca is one energy level smaller than Rb and Sr. Rb is to the left of Sr.
(d) Rb > Sr > Ca

45. (a) Kr, He, Ar (b) Sb, Te, Sn (c) K, Ca, Rb (d) I, Xe, Cs
SAMPLE PROBLEM
Ranking Elements by First Ionization Energy
PROBLEM:
Using the periodic table only, rank the elements in each of the following sets in order of decreasing IE1:
(a) Kr, He, Ar
(b) Sb, Te, Sn
(c) K, Ca, Rb
(d) I, Xe, Cs
PLAN:
IE decreases as you proceed down in a group; IE increases as you go across a period.
SOLUTION:
(a) He > Ar > Kr
Group 8A(18) - IE decreases down a group.
(b) Te > Sb > Sn
Period 5 elements - IE increases across a period.
(c) Ca > K > Rb
Ca is to the right of K; Rb is below K.
(d) Xe > I > Cs
I is to the left of Xe; Cs is further to the left and down one period.