1. Mr. Mellon Regents Chemistry
Unit 3: Periodic Table Have your Periodic Table out everyday for this unit
Mr. Mellon
Regents Chemistry

2. I. Historical Development of the Table
A. Dmitri Mendeleev (__________)
Arranged elements into table based on…
similarities in the physical and chemical properties
thought similarities were function of atomic mass
Noticed that some elements seemed out of order (Iodine and Tellurium)
Mendeleev Video Clip

3. I. Historical Development of the Table
1913
A. Henry Mosely (__________)
Established that properties of elements were functions of ____________
Atomic Number
1. Present table based on ________________
Atomic Number
2. Elements’ properties depend on ________________
Structure of atom
3. Properties of elements vary ________________
Systematically throughout the table

4. II. Period (or Rows)
Horizontal rows
Number at the beginning of the period indicates the principle energy level in which valence electrons are located
1 PEL
2 PEL
3 PEL
Periods 

5. II. Period (or Rows) 4 4 4 Not similar
Example:
A) What period is potassium and bromine in? ____
B) Based on the period, how many principal energy levels do
potassium and bromine have? _______________
____________________________________________
A) What period is potassium and bromine in? ______
B) Based on the period, how do the properties of potassium and bromine compare? _______________ 4 4
Properties change as you move across a period 4
Not similar

6. III. Groups(or Families)
Vertical Columns
Each group has similar chemical properties
Because each group has same number of valence e- (except groups 3-12)
# of
valence e- 1 2 3 4 5 6 7 8
Groups

7. II. Period (or Rows) 2 Similar (both have 2 valence e-) Example:
A) What group is magnesium and calcium in? ____
B) Based on the group, how do the properties of magnesium and calcium compare? _______________ 2
Similar (both have 2 valence e-)

8. III. Groups(or Families)
Sample Questions:
Which sequence of atomic numbers represents elements which have similar chemical properties?
A) 19, 23, 30, 36 C) 9, 16, 33, 50
B) 3, 12, 21, 40 D) 4, 12, 38, 88
Which two elements have the most similar chemical properties?
A) Aluminum and Barium C) Nickel and Phosphorous
B) Chlorine and Sulfur D) Sodium and Potassium

9. IV. Metals
Atoms that lose e- and form positive ions (cations) when bonding
Alloy:
Mixture of metals by melting them together

10. IV. Metals 1. Low ionization energy and electronegativity
Properties of Metals:
1. Low ionization energy and electronegativity
2. Good conductors of heat and electricity
3. Exhibit metallic luster (shine)
4. Malleability (can be pounded into thin sheets)
5. Ductility (can be pulled into thin wires)
6. More than 2/3 of the elements are metals
7. High densities
8. Mercury (Hg) is a metal which a liquid at room temperature
9. Most active metal (bottom left corner): ________
Fr (Francium)

11. CHECKS FOR UNDERSTANDING
IV. Metals
CHECKS FOR UNDERSTANDING
Which element is malleable and can conduct electricity in the solid phase? A) Iodine B) Phosphorous C) Sulfur D) Tin
What happens to metals when they bond? What would happen to their atomic size?
Where are the most reactive metals located? What about their atomic structure that makes them so reactive?
Lose electrons; become smaller
Bottom left corner; the electrons are far away (big atomic radius), so electrons can be easily removed (low ionization energy/electronegativity)

12. V. Nonmetals
atoms gain e- and form negative ions (anions) when bonding

13. V. Nonmetals 1. High ionization energy and electronegativity
Properties of Nonmetals:
1. High ionization energy and electronegativity
2. Poor conductors of heat and electricity
3. Brittle and hard
4. Low densities
F (Fluorine) (top right corner)
5. Most active nonmetal: ________
Graphite is an allotrope of carbon. It is used in pencils (brittle, soft, and low density)

14. CHECKS FOR UNDERSTANDING
V. Nonmetals
CHECKS FOR UNDERSTANDING
Which element is brittle and not a conductor of electricity? A) Sulfur B) Sodium C) Potassium D) Argon
What happens to nonmetals when the bond? What happens to their atomic radius when they bond?
Where are the most reactive nonmetals located? What about their atomic structure that makes them so reactive?
Gain electrons; become larger
Top Right corner (Group 17); small atomic radius so they attract electrons (High electronegativity/ ionization energy

15. VI. Metalloids Atoms that gain or lose e- and form ions when bonding
Have properties of both metals and nonmetals
Can be located using the “staircase” (see periodic table)
Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium

16. CHECKS FOR UNDERSTANDING
VI. Metalloids
CHECKS FOR UNDERSTANDING
Which element has both metallic and nonmetallic properties? A) Rb B) Rn C) Si D) Sr
Which list of elements contains 2 metalloids?
Si, Ge, Po, Pb C) As, Bi, Br, Kr
Si, P, S, Cl D) Po, Sb, I, Xe

17. VII. Periodic Properties
A. Covalent Atomic Radius:
½ of the distance between adjacent nuclei of the element

18. VII. Periodic Properties
Periodic Trend (See Ref Tabs – Table _____)
decreases
Covalent Atomic Radius ___________
as you move from ______________________________
Left to right across a period
PEL remains the same and outer e- get pulled closer to the nucleus
increases
Covalent Atomic Radius ___________
as you move from ______________________________
down a group
# of energy levels increase

19. VII. Periodic Properties
B. Ionic Radius:
A loss or gain of e- causes an increase or reduction in atom’s size
cations
Metals: __________ electrons when they form ions ( _____________ ) and ionic radius __________ than neutral atom
lose
smaller
2-8-1
2-8

20. VII. Periodic Properties
B. Ionic Radius:
Nonmetals: __________ electrons when they form ions ( __________ ) and ionic radius __________ than neutral atom
anions
gain
bigger
2-8-7
2-8-8

21. IV. Periodic Properties
Sample Questions:
Which element has an atomic radius that is greater than its ionic radius?
A) S C) F
B) K D) O
In period 4, the atom with the largest covalent radius is located in group…
A) 1 C) 3
B) 13 D) 18

22. VII. Periodic Properties
C. Ionization Energy:
Amount of energy needed to remove the most loosely bound e - (valence e -)

23. VII. Periodic Properties
Periodic Trend (See Ref Tabs – Table _____)
increases
Ionization Energy ___________
as you move from ______________________________
Left to right across a period
Number of protons and valence e- increases and size decreases, so e- are held tighter
decreases
Ionization Energy ___________
as you move from ______________________________
down a group
e- are farther away, so easier to remove e- and valence e- are shielded by inner e-

24. VII. Periodic Properties
D. Electronegativity:
Measure of atom’s attraction for electrons when bonded
Periodic Trend (See Reference Tables – Table _____):
Electronegativity ______________ as you move from ______________________________
Electronegativity ______________ as you move from _____________________________ S
increases
Left to right across a period
decreases
down a group

25. IV. Periodic Properties
Check for Understandings
What are the electronegativities for group 18 elements? Why do you think they have “this” electronegativity?
Which element attracts electrons the most when bonding?
A) Ca C) Br
B) Sr D) I
Which element gives off its valence electrons the easiest?
A) Ca C) Br
B) Sr D) I
They do not have electronegativity numbers. Why? Because they already have their 8 valence electrons (octet)

26. VIII. Groups within Groups
Alkali Metals
A. Group 1: ________________
All soluble (dissolves) in water and strongly basic
Hydrogen is the exception on the periodic table – it belongs nowhere : (
Brainiac – Alkali Metals
MYTHBUSTERS – ALKALI METALS
Part 1
Part 2

27. VIII. Groups within Groups
Alkaline Earth Metals
B. Group 2: ______________________
Have 2 valence electrons
Form +2 charge when they bond
In General for Groups 1 and 2:
As you move down, they become more reactive

28. VIII. Groups within Groups
CHECKS FOR UNDERSTANDING
As you move down groups 1 and 2 elements become more reactive. Explain why this happens based on atomic size and ionization energy/electronegativity.
What will be the charge on a Ca ion when it bonds?
Based on your answer to question 2, what happens to the atomic size once it becomes an ion?
Size increases, ionization energy decreases (easier to remove e-) so they become more reactive +2
Smaller (loses last energy level)

29. VIII. Groups within Groups
Transition Metals
C. Groups 3-12: ________________
Dense Metals and high melting points
Form multiple ions and less reactive than Groups 1 and 2
Form ions that have color

30. VIII. Groups within Groups
CHECKS FOR UNDERSTANDING
4. Identify the metal that has multiple oxidation states.
A) K B) Ba C) Be D) Pd
5. Which compound forms a green aqueous solution?
A) RbCl B) CaCl2 C) NiCl2 D) BeCl2
6. Which set of properties is most characteristic of transition elements?
Colorless ions in solutions, multiple positive oxidation states
Colorless ions in solutions, multiple negative oxidation states
Colored ions in solutions, multiple negative oxidation states
Colored ions in solutions, multiple positive oxidation states

31. VIII. Groups within Groups
Halogens
D. Group 17: ________________
Have 7 valence e-, become -1 charge ion
Mostly nonmetallic elements

32. VIII. Groups within Groups
Noble Gases
E. Group 18: ________________
All energy levels are full (2 or 8 valence electrons)
Do not combine with other elements to form molecules (exist as monatomic in normal room conditions)
They are stable
All other elements want to be like them

33. VIII. Groups within Groups
CHECKS FOR UNDERSTANDING
Which halogen is most reactive? Explain why, based on atomic size, electronegative/ionization energy.
Explain why noble gases don’t typically react with other elements?
F: smallest in size so attraction for electrons is very high (electronegativity)
Their outer energy level is completely full. They do not want to gain anymore e-

34. IX. Phases of Matter
All of the information on the Periodic Table is given at STP
STP -
Standard Temperature and Pressure
( 0oC and 1 atm/101.3 kPa (sea level pressure))
Gases -
H, N, O, F, Cl and Noble Gases
Liquids -
Br, Hg
Solids -
Everything else

35. X. Other Categories Diatomics - Molecule containing 2 identical atoms
Remember them:
H, O, F, Br, I, N, Cl (7-H club)
Radioactive -
An element that ALL its isotopes are unstable and break down spontaneously
Remember them:
Atomic # greater than 84 and 43 (Technitium), 61 (Promethium)

36. X. Other Categories Synthetic -
Man-made elements (all are radioactive as well)
Remember them:
Atomic # greater than 93 and 43 (Technitium), 61 (Promethium)

37. X. Other Categories Allotropes-
2 or more different structural forms of an element in the same phase
Remember them:
Examples: C (s) – Diamond, graphite, coal, and Buckminster
O (g) – O2 – Dioxygen- what we breath
- O3 – Ozone - Toxic
Diamond
Graphite
Coal
Buckminster

38. X. Other Categories Allotropes-
2 or more different structural forms of an element in the same phase
Remember them:
Examples: O (g) – Diamond, graphite, coal, and Buckminster
Diamond
Graphite
Coal
Buckminster