1. Chapter 6
The Periodic Table and Periodic Law

2. History of the Periodic Table’s Development
Antoine Levoisier
1790s compiled a list of known elements.
23 elements on the list.
Elements included gold, silver and other elements known since prehistoric times.

3. History of the Periodic Table’s Development
Knowledge explosion due to advances in scientific technology
Electricity allowed scientists to break down compounds into their basic elements
Spectrometer was used to identify newly isolated elements
Industrial Revolution
Many new chemistry-based industries (petrochemicals, soaps, dyes, etc.)
1860s s
Chemists agreed to use the Atomic Masses were standardize
Over 70 Elements Known

4. History of the Periodic Table’s Development
John Newlands
Developed the law of octaves
Every 8 elements, the properties repeat
Called a period
Based on atomic mass
Other scientists thought the naming of “Law of Octaves” to be unscientific as it was based on music
Meyer
Mendeleev
Moseley

5. History of the Periodic Table’s Development, Cont.
Meyer, Mendeleev and Moseley
Meyer and Mendeleev
Understood the correlation between atomic masses and elemental properties
Mendeleev organized the first periodic table
Left blank spaces where undiscovered elements would go
Able to predict properties of yet unknown elements, based on observed trends
Periodic Table not Fully Correct

6. History of the Periodic Table’s Development, Cont.
Meyer, Mendeleev and Moseley
Moseley
Reorganized the periodic table developed by Mendeleev
Included newly found elements
Discovered each element contains a unique number of elements in their nuclei
Rearranged elements by atomic number, not atomic mass
Periodic Law: Periodic repetition of chemical and physical properties that are arranged by increasing periodic number

7. Modern Periodic Table Groups and Periods
The Periodic Table will help you organize chemistry knowledge
Columns
Groups/Families of elements that have similar properties
Total 18 Groups
Rows
Periods of elements that repeat properties
Total of 7 periods

8. Groups and Families Periodic Tables

9. Modern Periodic Table Classifying Elements 1A) Alkali Metals
2A) Alkaline Earth Metals
Both 1A and 2A are chemically Reactive with Alkali being the most reactive of the two
3A) Boron Family
4A) Carbon Family
5A) Nitrogen Family
6A) Oxygen Family
7A) Halogen / Fluorine Family
8A) Noble Gas / Helium Family

10. Modern Periodic Table Classifying Elements
The B Group are the Transition Elements

11. Groups and Families Periodic Tables

13. Organizing the Elements by Electron Configuraton
Valence Electrons and the Period
Valence Electrons and Group/Families
Period denotes the highest level energy level
Group denotes the number of valence electrons

15. S, P, D and F Block Elements
As S-Orbitals holds maximum of 2 electrons, spans 2 groups P
As P-Orbitals hold maximum of 6 electrons, spans 6 groups D
Contains transitions metals and is the largest block of elements
Characterized by completely filled S orbitals and increasingly filled D orbitals
As D-Orbitals hold 10 electrons, spans 10 groups F
Contains inner transition metals
As F-Orbitals hold 14 electrons, spans 14 groups

16. Principal Energy Levels
The energy level denoted by the principal quantum number n.
The first element in a period introduces the new principal energy level.
Principal Energy Levels are broken down into sub-levels (S, P, F, D)
Period
Principal Energy Level
Element 1
n = 1
He, H 2
n = 2
Li, Be, B, C, N, O, F, Ne 3
n = 3
Na, Mg, Al, Si, P, S, Cl, Ar 4
n = 4
K, Ca, Ga, Ge, As, Se, Br, Kr 5
n = 5
Rb, Sr, In, Sn, Sb, Te, I, Xe 6
n = 6
Cs, Ba, Ti, Pb, Bi, Po, At, Rn 7
n = 7
Fr, Ra

17. Bohr Model of the Atom How to Draw a Bohr Model Draw the nucleus.
Write element symbol, the number of neutrons and the number of protons in the nucleus.
Draw the first energy level.
Draw the electrons in the energy levels according to the rules. Make sure you draw the electrons in pairs.
Keep track of how many electrons are put in each level and the number of electrons left to use.

18. Bohr Model of the Atom, Continued
Rules for Bohr Energy Levels
Level 1: Holds a Maximum of 2e
Level 2: Holds a Maximum of 8e
Level 3: Holds a Maximum of 8e
Level 4: Holds a Maximum of 18e.

19. Guided Practice on Bohr Models
Draw a Bohr Model for C
Element Symbol: C
Atomic Number: 6
Atomic Mass: 12
Protons: _____________
Neutrons: ______________
Electrons: ______________
Number of Energy Shells: ______________
Number of Valence Electrons (Outer Shell): ____________________________ C

20. Guided Practice on Bohr Models
Draw a Bohr Model for C
Element Symbol: C
Atomic Number: 6
Atomic Mass: 12
Protons:
Neutrons: 6
Electrons: 6
Number of Energy Shells: 2
Number of Valence Electrons (Outer Shell): 4 C
Protons: 6
Neutrons: 6

21. Guided Practice on Bohr Models
Draw a Bohr Model for C
Element Symbol: C
Atomic Number: 6
Atomic Mass: 12
Protons:
Neutrons: 6
Electrons: 6
Number of Energy Shells: 2
Number of Valence Electrons (Outer Shell): 4 C
Protons: 6
Neutrons: 6

22. Periodic Trends Atomic Radius Atomic Radius Period Trends:
Metals: Atomic radius is half the distance between adjacent nuclei in a crystal of the element
Elements that occur as molecules: Half the distance between nuclei of identical atoms that are chemically bonded together.
Period Trends:
Decrease from Left to Right
More valence electrons without higher level orbitals means a higher nuclear charge, condensing the atomic radius
Group Trends:
Increase from top to bottom
Increase in electrons, plus the addition of higher level orbitals.

23. Periodic Trends

24. Periodic Trends Ionic Radius
Ion: Atom or bonded group of atoms that has either a positive or negative charge
They have either gained or lost an electron
Ionic Radius: Atomic radius of an ion
When ions are formed, it is ALWAYS valence electrons that are either gained or lost
When lost (creating a positive CATion), the radius becomes smaller as are either fewer electrons or a completely empty orbital shell
When an electron is gained (creating a negative ANion), the radius becomes larger as there are both more electrons and they may be within higher level orbital shells.

25. Periodic Trends Ionic Radius Period Trends: Group Trends:
Increase from Left to Right
Left-side of the table form smaller positive ion (CATions)
Right-side of the table form larger negative ions (ANions)
Group Trends:
Increase from top to bottom
Increase in electrons, plus the addition of higher level orbitals.

26. Periodic Trends
Ionic Radius

27. Periodic Trends Ionization Energy
Ionization Energy: Energy required to remove an electron from a gaseous atom.
First Ionization Energy: The energy required to remove the first electron from an atom
Period Trends:
First ionization energies increase from left to right, due to the increased nuclear charge (more protons = stronger charge) on the valence electrons
Group Trends:
First ionization energies decrease from top to bottom on groups, due to the valence electrons being further away from the nucleus in higher level shells.

29. Periodic Trends Octet Rule Remember “Eight is Great”
Atoms tend to gain, lose or share electrons in order to get to 8 valence electrons

30. Periodic Trends Octet Rule and Electron Configuration
When gaining or losing an electron (creating Anions and Cations), the electron configuration needs to change
If losing an electron: remove it from the top-level orbital first
Li = 1S22S1
Li+ = 1S2
If gain an electron: add it to the top level orbital first and if that is full, add the next level orbital
F = 1S22S22P5
F- = 1S22S22P6

31. Periodic Trends Electronegativity
Electronegativity: Indicates the relative ability of an element to attract electrons into a chemical bond
Period Trends:
Increase as you move left-to-right
Group Trends:
Decrease as you move down a group
Lowest Electronegativity Energies in lower left
Highest Electronegativity Energies in upper right