1. The Periodic Table
Chapter 6.1

2. Periodicity
something that repeats in a specific manner.

3. Lists of known elements
In the 1790s Lavoisier complied a list of known elements (23)
Many new elements were discovered in the 1800s
electricity allowed compounds to be broken into elements
industrial revolution led to chemistry based industries
spectrometer allowed elements to be identified

4.
In the 1860s chemists agreed on a method to accurately determine atomic mass
By 1870 there were 70 known elements
chemists were overwhelmed learning the properties of so many new chemicals
think of a Walmart where nothing is organized. It’s all just thrown wherever and you have to search through all of it.

5. John Newlands
arranged elements by increasing atomic mass and realized properties were repeated after every 8th element. He called this the law of octaves (just like music):
element 1 and element 9 behaved similarly

6. John Newlands harshly criticized for his analogy to music
his rows became column in our periodic table

7. Dmitri Mendeleev
showed a connection between atomic mass and properties
arranged elements by increasing atomic mass in columns and grouped by physical and chemical properties

8. Dmitri Mendeleev
predicted the existence and properties of unknown elements
He left gaps for these unknown elements
some elements were ordered incorrectly

9. Henry Mosely discovered each element has a unique number of protons
arranged elements by increasing atomic number (protons)

10. Henry Mosely saw clear periodic pattern of elements (periodic law)
brought order to seemingly unrelated facts

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

12. Boxes in the Periodic Table
each box gives:
element name
element symbol
atomic number (= number of protons)
atomic mass (weighted average mass of all isotopes of that element)

13. Periods:
horizontal rows ( ) on the periodic table
there are 7 periods
the periods correspond with the number of electron shells or energy levels
As you go from left to right across a period, the number of protons (atomic number) increases by 1.

14. Groups/Families: The vertical columns on the periodic table.
The elements in any group of the periodic table have similar physical and chemical properties because they have the same number of valence electrons!

15. Question!
How are periods and groups/families on the periodic table different? Use this sentence stem: One way periods and groups/families on the periodic table are different is …….

16. Modern Periodic Table
Group A elements are called representative elements
Group B elements are called transition elements

17. Classification Groups
elements can be classified as:
metals
nonmetals
metalloids
divides along the zigzag line

19. Metals On the left side of the periodic table: High luster (shiny)
Exception: Hydrogen IS NOT a metal
High luster (shiny)
solids at room temperature
Good conductors electricity and heat
Ductile (forms wires)
Malleable (bendable/shapable)
all group B elements are metals

20. Alkali Metals

21. Alkali Metals Soft, shiny metals that can be cut with a butter knife
alkaline means base (high pH)
group 1A elements (except hydrogen)
very reactive elements
Reacts violently with water
never found as elements in nature (always in a compound)

22. Alkali Metals
Alkali Metal Video

23. Alkaline Earth Metals

24. Alkaline Earth Metals group 2A elements
reactive, but slightly less reactive than alkali metals (group 1A)
found in the earth’s crust
Emeralds are made of beryllium

26. Transition Metals

27. InnerTransition Metals
These elements are also called the rare-earth elements.
InnerTransition Metals

28. Transition Elements transition metals inner transition metals
conduct heat and electricity
high luster when polished
inner transition metals
lanthanide series (phosphors that emit light when struck by electrons. how television works)
actinide series (along the bottom)

30. Nonmetals shown in yellow in your textbook
upper right hand corner of periodic table
gases or dull looking brittle solids
do NOT conduct heat or electricity well
Br is the only liquid nonmetal

31. Halogens

32. Halogens Group 7A elements extremely reactive
halogen comes from a Greek word meaning giving rise to salt
combine with other elements to form salts

33. Noble Gases

34. Noble Gases Group 8A All gases
Unreactive: inert, stable, don’t form compounds
Have complete valence shells

36. Metalloids shown in green boxes in your textbook
along the stair step line
have physical and chemical properties that are
metal like
nonmetal like
Silicon is used in computer chips
Germanium is used in solar cells

37. Periodic Trends

38. Atomic Radii
Atomic radius – one half the distance between the nuclei of two atoms of a molecule.

40. Atomic Radii Decrease across the periods.
Caused by the increasing positive charge of the nucleus
Increase down the group ( A few exceptions)
Outer electron is in higher energy levels – farther from the nucleus.

41. Group trends As we go down a groupH
As we go down a group
Each atom has another energy level (electron shell),
So the atoms get bigger. Li Na K Rb

42. Ionic Radii Ion: an atom or a bonded group of atoms that has a charge
Cation – positive ion
Loss of electron; decrease in radius (smaller)
Protons pull harder on the electrons to pull them in tight
Anion – negative ion
-Gain of electron; increase in radius (larger)
-the nucleus is less powerful than the electron cloud so it expands.

43. Ionic Radii Metals on the left form cations
Nonmetals on the right form anions
As you move to the right on the Periodic Table, the size of an ion decreases.
As you move down a column, the size of an ion increases

44. Question
What is the difference between atomic radius and ionic radius?
Write this Stem in your notes: The difference between atomic and ionic radius is ……
When you are finished writing, put pencil down and look up.
When everyone is finished, we will share.

45. Ionization Energy
The energy required to remove an electron from an atom
As you move across a period, the ionization energy increases.
Down the Groups, the ionization energy decreases.
Caused by the increased size of the atoms. The electrons that are farther from the nucleus are easier to remove

46. Ionization Energy

47. Another Way to Look at Ionization Energy

48. Electronegativity Table of the Elements
The pull a nucleus has on the electrons of a neighboring atom during a chemical bond.
Metals lose electrons so they have low electronegativity's.
Non-metals gain electrons so they have high electronegativity's (exception: noble gases are NOT electronegative)
Generally, electronegativity increases from left to right and decreases from top to bottom.
Periodic table of electronegativity using the Pauling scale
See also Periodic table

49. Electronegativity

50. Summation of Periodic Trends