1. The Periodic Table and Periodic Law
Chapter 6

2. Section 6.1: Development of the Modern Periodic Table
Late 1790’s- Lavoisier compiled a list of 23 elements known at the time
By known elements
John Newlands
Arranged elements by increasing atomic mass
Noticed properties repeated every eighth element (periodic)
Law of Octaves

3. Dmitri Mendeleev Russian 1st periodic table
Organized elements by properties
Arranged elements by atomic mass
Predicted existence of several unknown elements
Element 101 Mendeleevium (Md)

5. Henry Moseley
1913-performs experiments to determine the atomic number of the known elements
Afterwards arranges the elements in the periodic table listing them by increasing atomic number instead of by mass

6. Periodic Law
When the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

7. The Modern Periodic Table
Groups- aka families (vertical columns)
Each group is numbered 1-8 followed by the letter A or B
Representative Elements- designated with an A (1A-8A)
Transition Elements- designated with a B (3B-12B)
18 total groups
elements of any one group have similar physical and chemical properties

8. Periods- horizontal rows
7 total periods
element properties change as you go across each row
the pattern of properties repeats from one period to the next

9. Classifying the Elements
Three main classifications for the elements
Metals
Nonmetals
Metalloids

10. Metals Physical Properties Chemical Properties
Luster (shininess)
Good conductors of heat and electricity
High density (heavy for their size)
High melting point
Ductile (most metals can be drawn out into thin wires)
Malleable (most metals can be hammered into thin sheets)
Chemical Properties
Easily lose valence electrons
Corrode easily
Alkali Metals- group 1A elements (except hydrogen)
Alkaline Earth Metals- group 2A elements

11. Metals Con’t. Transition Metals Inner Transition Metals
Group B elements
Inner Transition Metals
Lanthanide- used as phosphors (substances that emit light when struck by electrons)
Actinide

12. Nonmetals Physical Properties No luster (dull appearance)
Poor conductor of heat and electricity
Brittle (breaks easily) or gaseous
Not ductile
Not malleable
Low density
Low melting point
Bromine is the only nonmetal liquid at room temperature
Chemical Properties
 Tend to gain valence electrons

13. Nonmetals Con’t Halogens Noble Gases Group 7A Extremely Reactive
Extremely Unreactive

14. Metalloids Bordering the stair-step line Physical Properties Solids
Can be shiny or dull
Ductile
Malleable
Conduct heat and electricity better than nonmetals but not as well as metals

17. Elements in the same group on the periodic table have similar chemical properties because they have the same valence electron configuration

18. Section 6.3: Periodic Trends
The electron cloud surrounding the nucleus is based on the probability and does not have a clearly defined edge
Atomic size is defined by how closely an atoms lies to a neighboring atom

19. Atomic Radii Trend Trends within periods Trends within groups
Generally decreases as you move left-to-right across a period (row)
Trends within groups
Generally increases as you move down a group

20. Ionic Radius
An ion is an atom or a bonded group of atoms that has a positive or negative charge
When atoms lose electrons and form positively charged ions, they always become smaller
When atoms gain electrons and form negatively charged ions, they always become larger

21. Lose Electrons  Smaller ionic radii
Gain Electrons  larger ionic radii

22. Ionization Energy (I.E.)
Ionization Energy- the energy required to remove an electron from a gaseous atom
1st Ionization Energy- removes the 1st electron
2nd Ionization Energy- removes the 2nd electron… and so forth
I.E. is an indication on how strongly an atom’s nucleus holds onto its valence electrons

23. Octet Rule- atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons

24. Octet Rule- atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons
Hydrogen and Helium are exceptions (they’ll be happy with 2 V.E.)
Determines the types of ions likely to form
Elements on the right side tend to gain electrons
Elements on the left side tend to lose electrons

25. Electronegativity
Indicates the relative ability of its atoms to attract electrons in a chemical bond
Noble gases form very few compounds so they are left out
In a chemical bond, the atom with the greater electronegativity more strongly attracts the bond’s electrons

27. In Summary Atomic radius decreases Ionization energy increases
Electronegativity increases
Ionization energy decreases
Electronegativity decreases
Atomic radius increases 1A 2A 3A 4A 5A 6A 7A

28. Matching Words for Test
Electronegativity
Ionization energy
Atomic radius
Metal
Transition metal
Anion
Periodic law
Cation
Period
Group
Electrons
Nonmetal

29. Homework
Page
#29-#38
#40-#45
#47-#76