1. The Periodic Law (Periodic Table)
CHAPTER FIVE

2. Brief History
Original periodic table was constructed by Dmitri Mendeleev. This periodic table consisted of about 60 elements and was arranged in order of increasing atomic mass

3. Modern Periodic Table
Our periodic table is based on the work of Henry Mosely, who arranged the elements in order of increasing atomic number

4. Periodic Law
Mosely’s and Mendeleev’s periodic table follows periodic law:
This means that if elements are arranged in increasing atomic #, they will fall into groups that have similar properties.

5. Modern Periodic Table 18 vertical group/families 7 horizontal periods
Divided into two main parts, metals and nonmentals.

6. Group 1 Elements Alkali Metals Most reactive of the metals
Mostly Soft Solids

7. Group 2 Elements Alkaline Earth Metals Still very reactive
More dense than the group 1 metals

8. Groups three through twelve
Transitional Metals
Elements “transition” from Metals to non-metals as you move across the table
metallic properties

9. Group 17
Halogens
Non-metals
most reactive of nonmetals.

10. Group 18
Noble gases
Nonmetals
Least reactive of non-metals

11. Left Side of the periodic table
Metals
Shiny
Malleable
Ductile
Conducts electricity
Conducts Heat
Mostly solids

12. Inbetween are the “Others”
Other Metals (Have metallic properties)
Al, Ga, In, Sn, Bi, Pb, Tl
Metalloids-Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium
Properties of both metals and non-mentals
Semiconductors-used in electronics
Other Non-Metals (Have non-metal properties)
C, N, O, P, S, Se, H

13. Right side of periodic table
Non-Metals
Do not conduct electricity or heat well
Some brittle solids
Some gasses

14. Check for understanding
Which group/family is each element in? Al Ar K Pd Br Ca Zn Si
Based on the group/family each element below are in, name 2 properties of :
9. K
10. P
11. Cl
12. Ga

15. Periodic Trends
Elements have characteristics that tend to increase or decrease as one moves along a row or column of the periodic table of elements.

16. Atomic Radii
Atomic Radii-The distance from the center of the nucleus to the edge of the atom’s electron cloud.
Atomic Radii

17. Atomic Radii Trending Activity
Grapher
Straw Cutter
Recorder
We will use our current knowledge of the atom to try and predict the trend for atomic radii.
We will then test our hypothesis by actually graphing real data and then making a 3-D model of the trend.

18. Atomic Radii Continued
Trend in each period
Why do you think the radius decreases to the right if there are more protons to the right? Shouldn’t that make the radius increase?
As there are more protons they pull more strongly on the electrons that are surrounding them.
Each period is within the same energy level.

19. Atomic Radii Continued
Trend in each group
Why do you think the radius increases as you go down a group if more protons means they pull harder on the electrons?
As you go down a group you are adding energy levels which makes the radius increase.

20. Atomic Radii Continued
Periodic Table Trend:
Increases to the left
Increases going down
Increasing Size

21. Atomic Radii Practice K or Ni Ne or Xe Rb or In 4. Al, K, Ne, H
In each pair which of the following has the largest Atomic Radii?
K or Ni
Ne or Xe
Rb or In
Arrange the following in order of increasing atomic radii?
4. Al, K, Ne, H
5. Will a larger atomic radii make an atom more or less likely to give away an electron?

22. Quiz
Place the following in order using decreasing Atomic Radii : Au, Ba, O, Cl & Pb
Cl or I
Which of the above pair has the largest atomic radii?
Why does the table trend that way?
Who created the 1st periodic table?
What was the 1st periodic table arranged by?
The vertical columns are called what?
Elements within the same column will have _________ properties.
What is the name of each of the following groups? 18 2 1
Which group name does Ge fall under?
Name 4 popertiesA

23. Ionization Energy (IE)
1st Ionization Energy-Energy required to remove one electron from an un-bonded atom. (individual atoms)
Basically: How hard is it to get an electron away from an atom?
No, Mine!
Mine! e-

24. Ions
ION-an atom that has a positive or negative charge.

25. Ionization Energy (IE)
A lost electron will create a Positive Ion
Positive Ion is a Cation + + + + + + +
Pawsitive : )

26. Ionization Energy (IE)
A gained electron will create a negative ion
Negative ions are called Anions

27. Ionization Energy (IE) Continued
Trend across a period?
Decreases to the left
Trend in a group/family?
Decreases going down
Which Group would have the lowest first Ionization energy? (who is it easiest to take an electron from?)
Group 1
Why?
They want to get rid of that 1 valence electron
Which group would have the highest first ionization energy?
Group 18
They do not want to lose one of their 8 valence electrons ( they are happy the way they are)

28. Ionization Energy Periodic Table Trend: Decreases to the left
Decreases going down
Decreasing
Decreasing

29. Ionization energy practice
Which element within the following pairs has the highest ionization energy?
K or Be
B or Ga
O or Ca
Ar or Sb
Arrange the following in decreasing Ionization energy (meaning from Highest to lowest)
Li, O, C, K, Ne, F

30. Electronegativity
Electronegativity-Measurement of how strongly one atom attracts the electrons of another atom in a compound.
Developed by Linus Pauling
Which element do you think would be the most electronegative?
Fluorine All other values are calculated in relation to Fluorine’s value.
Scientest just picked the number 4. It wasn’t really based on anything.

31. Electronegativity & (FON)
Oxygen, Nitrogen and then the other halogens are the most Electronegative after fluorine.
F, O, N – Top 3 highest electronegativity

32. Electronegativity Periodic Table Trend: Decreases to the left
Decreases going down
Decreasing
Decreasing

33. Electronegativity Practice
Which of each pair has the greatest EN?
a. Ca or Ga
b. Br or As
c. Li or O
d. Ba or Sr
e. Cl or S
f. O or S
Rank the following elements by increasing EN: sulfur, oxygen, neon, aluminum.
Answer: Ne,Al,S,O

34. Definition in your own words
Trending Challenge
 Terms
Definition in your own words
Single atoms or bonded atoms?
Element with smallest
Element with largest
Atomic Radii
Ionization Energy
Electro-negativity

35. Review
1. The elements characterized as nonmetals are located in the periodic table at the (A) left; (B) bottom; (C) center; (D) top right 2. Which is the atomic number of an alkali metal? (A) 10; (B) 11; (C) 12; (D) Which element is a halogen? (A) iron; (B) nitrogen; (C) iodine; (D) neon 4. Which Group 17 element has the least tendency to gain electrons? (A) fluorine; (B) iodine; (C) bromine; (D) chlorine. 5. The alkaline earth element having the largest atomic radius is found in Period (A) 1; (B) 2; (C) 6; (D) Which of the following atoms will lose an electron the easiest? (A) potassium; (B) calcium; (C) rubidium; (D) strontium

36. Electron Affinity
Electron Affinity-The energy change that occurs when an individual atom gains an electron.
The more an atom “loves” getting another electron the more the energy it will release.
. . _
. . +
Electron
Atom

37. Electron Affinity Which group is “happiest” to take on an electron?
Group 17 Why?
They are 1 electron away from a full outer shell (Valance Shell)

38. Electron Affinity Group 1 and Group 18? Why?
Which groups care nothing for additional electrons?
Group 1 and Group 18? Why?
Group 18 is totally happy with their 8 electrons
Group 1 is closer to being happy by giving away it’s 1 valance electron.

39. Electron Affinity Periodic Table Trend: Decreases to the left
Decreases going down
Decreasing
Decreasing

40. Electron Affinity Arrange by increasing Electron Affinity
Which of the following has the greatest electron affinity?
Al or Br
O or C
Xe or F
Arrange by increasing Electron Affinity
Cl, K, Fr, I
Answer:Fr, K, I, Cl