1. Introduction to The Periodic Table
The “Father” of the Periodic Table
was Demitri Mendeleev.
He arranged the elements according to properties the elements have in common, also by atomic mass.

2. Modern Periodic Table
The Periodic Table is NOW arranged by increasing atomic NUMBER
Recall: Atomic Number is the number of protons in the nucleus of an atom
Periodic Law – When elements are arranged in order of increasing atomic number, certain sets of properties occur periodically

3. Let’s look at the Periodic Table:

4. Periods of the Periodic Table
Horizontal rows (1-7) read from left to right are called periods
The first element in each period has a single electron in its valence shell
Each period ends with a noble gas

5. Group or family vertical (up and down) columns (1-18)
As you head down a group
the number of valence electrons remains the same,
but the principal energy level increases
In Groups 1, 2, 13-18,
the last digit of the group number
corresponds to the number of valence electrons,
Group 1 has 1 valence electron
Group 2 has 2 valence electrons
Group 13 has 3 valence electrons
Group 18 has 8 valence electrons

7. Some Group Names Group 1: ALKALI METALS (Except Hydrogen)
Group 2: ALKALINE EARTH METALS
Group 17: HALOGENS (diatomics)
Group 18: NOBLE GASES

8. Natural State of Elements
Most are solids (in Black)
2 liquids: Br and Hg (in Blue)
Gases: H, O, N, F, Cl, and group 18 (in Red)
Some elements are diatomic
Remember:
Br I N Cl H O F

9. Allotropes Allotropes are elements that come in different forms.
Ex. Carbon comes as:
Diamond
Graphite
Coal
Nanotubes
Buckyball
Ex. Oxygen comes as:
Oxygen (O2)
Ozone (O3)
The differences among the allotropic forms is due to the atomic arrangement.
They have different chemical and physical properties

10. Let’s Label Our “Blank” Table
Separate the metals from the nonmetals
Draw in the “staircase”
This line divides the table into two parts:
Metals (on the left)
Nonmetals (on the right)
Metalloids (semimetals) ON the stairs
Except Aluminum and Polonium (ALPO)

11. Let’s Label Our “Blank” Table
Label group numbers
Label period numbers
Separate solids, liquids, gases (label and color)
Label transition elements
(groups 3-11) are all special metals which produce
colored solutions
The two bottom rows, which are not connected to the periodic table, have their own names:
top row- lanthanides
bottom row- actinides

12. (groups 3-11) are all special metals which produce
Transition elements
(groups 3-11) are all special metals which produce
colored compounds
The two bottom rows, which are not connected to the periodic table, have their own name: The top row are called lanthanides. The bottom row are called actinides.

13. Characteristics of Metals:
Have metallic luster
Good conductors of heat & electricity
Malleable
Ductile
Solids at room temp (except for Hg)
Tend to lose electrons in a chemical reaction
Form cations
React with acids (HCl) to form Hydrogen Gas
Are fairly reactive due to:
----

14. 2 factors: The positive charge of the nucleus:
increases from Left to Right
The hold on valence electrons: (electronegativity)
Metals on the Left have a weaker hold
on the valence electrons

15. Metallic Character (this means acts like a metal)
The most metallic elements are alkali metals (group 1).
They are the most reactive metals.
This is due to their large size & small nuclear charge
The 1 valence electron is very easily lost
A typical metal has:
low electronegativity low ionization energy large radius.

16. The Trends:
As we go down in a group, the metallic character increases. Therefore, Fr has the most metallic character.
As we go from left to right in a period metallic character decreases.

17. Nonmetallic Character
Brittle
Lack luster
Poor conductors of heat & electricity
Generally gain electrons in chemical reactions
Form Anions
At room temp are gases or solids (except Bromine- liquid)
High electronegativity
High ionization energy
Small radius

18. Nonmetallic character increases left to right:
HALOGENS:
Most reactive group of nonmetals
Due to: high nuclear charge and
small atomic size
Gain electrons VERY easily
in chemical reactions

19. Nonmetallic behavior decreases
The Trend:
Nonmetallic behavior decreases
from top to bottom
within a family

20. Some Vocabulary:
Electronegativity

21. Electronegativity
The ability of an atom to attract shared electrons to itself
Fluorine has the highest ability to attract an electron.
It is given an arbitrary value of 4.0
(see table “S”)
The values for the other elements are based on the value of fluorine.

22. Electronegativity Trend
In general, as an atom’s electronegativity increases, it becomes easier for the atom to gain electrons

23. The Electronegativity Trend
Increases from left to right across a period
WHY?
More attraction of the electrons by the nucleus
(another proton is added to the nucleus with each succeeding element so the nucleus becomes more positively charged)
The outermost electron that is added is in the same principal energy level
TREND:
Decreases from top to bottom within a group
WHY?
Because the outermost electron is in a new principal energy level which is farther away from the nucleus
The nucleus’ attraction for the electron is weaker because its shielded from the electrons by having many principle energy levels

24. Ionization Energy Ionization Ionization energy First ionization energy
The process of making an ion by losing an electron
Ionization energy
The minimum amount of energy needed to remove the outermost electron from an atom
First ionization energy
The energy needed to remove the first outermost electron
(see table “S”)
Ex Li + ionization energy Li e -1

25. Ionization Energy Trend
In general, as ionization energy increases, it becomes more difficult to remove an atom’s outermost electrons

26. The Ionization Energy Trend
Increases from left to right across a period
WHY?
More attraction of the electrons by the nucleus
(another proton is added to the nucleus with each succeeding element so the nucleus becomes more positively charged)
The outermost electron that is added is in the same principal energy level
TREND:
Decreases from top to bottom within a group
WHY?
Because the outermost electron is in a new principal energy level which is farther away from the nucleus
The nucleus’ attraction for the electron is weaker because its shielded from the electrons by having many principle energy levels

27. Outermost Electron
Ionization energy (table “S”)
Element H
1s1
1312 Li
2s1
520 Na
3s1
496 K
4s1
419 Rb
5s1
403 Cs
6s1
376

28. Atomic Radius Refers to the size of the atom
It is a measure of one half the distance between two nuclei of the same atom.
The larger the radius, the larger the atom.

29. Atomic Radius Trend
Atomic radius does not simply increase as the number of subatomic particles do

30. The Atomic Radius Trend
Decreases from left to right across a period
WHY?
There is a greater attraction for the electrons by the nucleus.
Electrons are being filled in the same principal energy level (approximately the same distance from the nucleus).
Number of protons are increasing in the nucleus which increases the nucleus’ pull for the electrons.
TREND:
Increases from top to bottom within a group
WHY?
Electrons are being added to new principal energy levels which are farther away from the nucleus.

32. Ionic Radius The size of the atom after it becomes an ion
Metallic atoms decrease in size when they become ions
WHY?
They lose electrons so less PEL’s are occupied
Nonmetallic atoms increase in size when they become ions
WHY?
They gain electrons which decreases the attraction between the nucleus and the electrons

33. Ionic Radius

34. Decreasing atomic radius Decreasing metallic character Increasing electronegativity Increasing ionization energy 1 1 1 1 1 1
Decreasing electronegativity
Decreasing ionization energy
Increasing metallic character
Increasing atomic radius

35. 1 1 1 1 1 1 Decreasing atomic radius Decreasing metallic character
Increasing electronegativity
Increasing ionization energy 1 1 1 1 1 1
Decreasing electronegativity
Decreasing ionization energy
Increasing metallic character
Increasing atomic radius