1. Periodic Trends & the Periodic Table

2. Periodic Table
Periodic Table – arrangement of elements in order of increasing atomic number with elements having similar properties in vertical columns
Groups – vertical columns
Periods – horizontal rows

3. Group Names Group Name 1A Alkali Metals 2A Alkaline Earth Metals
Chalcogens
Halogens
Noble Gases

4. Groups Representative elements – group A elements
Transition elements – group B elements
Lanthanide and actinide series = inner transition metals

5. Groups
The group tell you the number of valence electrons that the element has
Valence electrons are electrons in the outermost shell of the atom
All group 1A elements have 1 valence electron. Likewise, all group 8A elements have 8 valence electrons.

6. Octet rule
The maximum number of electrons that the outer energy level can hold is 8.
Valence shell = outer energy level
All elements try to establish an outer energy level like the noble gases. They do this by gaining or losing electrons.

7. Oxidation numbers
The charge an element would have if it released or obtained electrons to look like a noble gas.
Metals release electrons
Nonmetals obtain electrons

8. Predict the oxidation numbers for the following
A. Al
B. Mg
C. N
D. Na
E. Cl

9. Characteristics
Elements in the same group exhibit similar chemical characteristics due to the fact that they all have the same number of valence electrons.
The most stable number of valence electrons is 8
This is called an octet

10. Charges
Every element wants 8 valence electrons to become stable. They will gain or lose valence electrons to form an octet
For example…Group 1A elements have 1 valence electron. They can either gain 7 electrons to have an octet or lose 1.
What is easier?
Lose 1
If an element loses 1 electron (1 negative charge) what charge will the resulting ion have? +1

11. Charges Let’s go to group 7A. This group has 7 valence electrons
It can either loose 7 or gain 1
What is the easiest?
Gain 1
What will be the resulting charge if the element gain 1 electron (1 negative charge)? -1

12. Physical States and Classes of the Elements
The majority of the elements are metals. They occupy the entire left side and center of the periodic table.
Nonmetals occupy the upper-right-hand corner.
Metalloids are located along the boundary between metals and nonmetals

13. Metals
Metals are elements that have luster, conduct heat and electricity, and usually bend without breaking.

14. Transition Metals
The elements in Groups 3 through 12 of the periodic table are called the transition elements.
All transition elements are metals.
Many transition metals can have more than one charge

15. Inner Transition Metals
In the periodic table, two series of elements, atomic numbers and , are placed below the main body of the table.
These elements are separated from the main table because putting them in their proper position would make the table very wide.
The elements in these two series are known as the inner transition elements.

16. Inner Transition Metals
The first series of inner transition elements is called the lanthanides because they follow element number 57, lanthanum.
The second series of inner transition elements, the actinides, have atomic numbers ranging from 90 (thorium, Th) to 103 (lawrencium, Lr).

18. Non Metals
Although the majority of the elements in the periodic table are metals, many nonmetals are abundant in nature
Most nonmetals don’t conduct electricity, are much poorer conductors of heat than metals, and are brittle when solid.
Many are gases at room temperature; those that are solids lack the luster of metals.

19. Properties of Metals and Nonmetals

20. Metalloids
Metalloids have some chemical and physical properties of metals and other properties of nonmetals.
In the periodic table, the metalloids lie along the border between metals and nonmetals.

21. Electron Dot Structures
An electron dot structure consists of the elemental symbol surrounded by dots which represent valence electrons

22. Examples Draw the electron dot structure for Na
Draw the electron dot structure for Al
Draw the electron dot structure for Br

23. Periodic Trends
Periodic Trends are trends that occur across the periodic table and down the periodic table
They include: atomic radius, Ionization energy, electro negativity, metallic character, and ionic radius

24. Atomic Radius
Atomic Radius – size of the atom 
Decreases
Increases 

25. Atomic radius
The distance from the outer edge of the electron cloud to the nucleus.
The radius increases as the principle quantum number increases. So elements increase going from top to bottom.
The period they are in increased, radius increases.

26. As you move from left to right across the period things change.
The # of protons in the nucleus increases. This causes the electrons to be attracted to the nucleus more and the size of the elements decrease.
As you move from left to right radius decreases.

27. Which element in the pair is larger?
A. Sn, Sr
B. Cl, I
C. S,P
D. Ac, U
E. Na, Rb
F. B, Al

28. Determining the Atomic Radius of a Nonmetal (Chlorine)
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29. Determining the Atomic Radius of a Metal (Molybdenum)
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30. Ionization Energy
Ionization energy – the ability to pull off 1 electron 
Increases
Decreases 

31. Ionization energy
The energy required to remove the most loosely held electron from an element.
Large radii elements lose electrons easily
Small radii elements require energy to remove electrons.

32. Metals- don’t like electrons lose them easily
Nonmetals – like electrons, want to keep them, require energy to remove them.

33. Electro negativity
Electro negativity – the ability of an atom to attract another atom 
Increases
Decreases 

34. Metallic Character
Metallic character – how much like a metal the element is 
Decreases
Increases 

35. Electron affinity
The ability of an atom to attract electrons to itself.
Metal = low affinity
Nonmetals = high affinity
Large radius = low affinity
Small radius – high affinity

36. Metals and nonmetals Metals tend to lose electrons.
Nonmetals tend to gain electrons.
The goal is to get enough electrons in the outer energy level to look like a noble gas.
Every electron lost leaves behind a net + charge.

37. Energy electron gained causes a net – charge.
These charges effect the radius of the elements.
Elements with charges are called ions

38. Ionic radius
The more + charge and ion has the greater the ability to attract electrons to itself and is therefore smaller.
The more – charge an ion has the more electrons it has pulling away from the nucleus and therefore they are larger.

39. Which is larger?
A. Ca, Ca+2
B. F-, Cl-
C. As-, P-3
D. Pb, Pb+4

40. Ionic Radius
When you talk about ionic radius, you are comparing an atom and its ion
When an atom has a negative charge, you have added electrons
Which makes it bigger
For example, which will be larger:
Cl or Cl-1

41. Ionic Radius
When an atom has a positive charge, you have taken away electrons
Which makes it smaller
For example, which will be larger:
Na or Na+1

42. Periodic Table Trends Click in this box to enter notes.
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43. Ionic Radii Click in this box to enter notes.
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