1. The Periodic Table
Unit 2 – Lecture 4

2. Periodic Table Describes trends in physical and chemical properties
number of electrons, protons, neutrons
charge
reactivity
type of element

3. Properties Chemical Properties are based on the number of valence e-s
Elements in same group/family elements have same # of valence e-s
group 1 = 1, group 2 = 2
group 13-18, drop the “1” in front of the group #
ex: 13 = 3, 14 = 4
Helium has 2
Groups 3-12 use a different set of electrons, so it doesn’t follow the typical pattern

4. Charge Recall: “Octet Rule”
atoms will gain, lose, or share e-s to become chemically stable [8 e-s in valence shell]
PT indicates charge by groups as well
again, groups 3-12 are left out of this

5. Charge – cont’d
Groups 1 = +1, 2 = +2, 13 = +3
want to lose electrons

6. Charge – cont’d Group 14 = +/- 4  will gain or lose electrons equally
gain/loss depends on what it bonds to

7. Charge – cont’d Groups 15 = -3, 16 = -2, 17 = -1, 18 = 0
want to gain electrons

8. Charge – cont’d group 18 will not gain, lose, or share e-s
[bc they have 8 e-s anyway]

9. Charge – cont’d
Which is the more “positive term:
CAT? or
ONION?

10. Charge – cont’d Useful chemistry terms:
cation – positively charged atom
mostly metals
anion – negatively charged atom
mostly non-metals

11. Oxidation #
Oxidation Number – the number of e-s an atom will gain, lose, or share in order to become stable
basically the same as the charge on the PT
again, leave out groups 3-12
GROUP number indicates the number of outer-shell e-s
groups 1, 2, then groups (except He)
Always 4 or less [+ or -]

12. Oxidation/Charge Numbers/

13. In order to become stable…
…an Oxygen atom an will…
lose 6 e-s gain 6 e-s lose 2 e-s gain 2 e-s OR none of the above
…a Calcium atom will…
lose 6 e-s gain 6 e-s lose 2 e-s gain 2 e-s OR none of the above
… a Sodium atom will…
lose 7 e-s gain 7 e-s lose 1 e-s, gain 1 e- OR none of the above

14. In order to become stable…
…a Bromine atom an will…
lose 7 e-s gain 7 e-s lose 1 e-s gain 1 e-s OR none of the above
…a Xenon atom will…
lose 8 e-s gain 8 e-s lose 0 e-s gain 0 e-s OR none of the above

15. The Periodic Table
Periodic = in a regular, repeating fashion Early designs of the PT were based on use, physical properties, and even spelling.

19. Mendeleev’s Contributions
Organized first working Periodic Table
according to chemical properties and atomic mass
Left gaps for undiscovered elements
He was able to predict many properties of these undiscovered elements based on their location

20. Periodic Table – cont’d
column = group/family
elements in a family have the same chemical properties [valence e-s, reactivity…]
row = period
properties of elements repeat across a period [size of atom, ease of losing e-s]

21. Group 1
Alkali Metals
Highly reactive metals
2ectron

22. Group 2 Alkaline Earth Metals Reactive metals
Have two outer shell electrons

23. Groups 3-12 Transition Metals “normal” metals
have one to ten outer shell electrons

24. Groups 3-12 cont’d
Lanthanide (57-71) & Actinide (89-103) series can be considered to be “inner” transition metals.

25. Metals vs. Non-Metals Metals Non-Metals Location left of the “stairs”
right of the “stairs
Appearance
lustrous
waxy or dull
“Shape-ability”
malleable & ductile
brittle
Conductivity [heat & electricity]
very good
poor - better as insulators
Physical State
solid at room temp [except Hg]
gas or solid at room temperature [except Br]
Charge
typically cations
typically anions

26. Metalloids May have properties of metals and nonmetals
Located on the stair-step
Some are semiconductors: they only conduct electricity under certain conditions
This makes metalloids excellent switches for computers

27. Group 17 Halogens Means “Salt Former” Highly reactive nonmetals
Have seven outer shell electrons

28. Group 18 Noble Gases Completely unreactive nonmetals
Will not bond with any atom
Have a full outer shell of electrons
Eight for all but Helium
He has two outer shell electrons

29. Practice Which group is known as the Halogens?
Group 1, Group 2, Groups 3 – 12, Group 17, Group 18
Which group has a stable number of outer shell electrons?
Group 1, Group 2, Groups 3 – 12, Group 17, Group 18
What is the group name for Group 2?
Alkaline Earth Metals, Alkali Metals, Halogens, Transition Metals, Noble Gases

30. Practice Which group is known as the Transition Metals?
Group 1, Group 2, Groups 3 – 12, Group 17, Group 18
Which group has two outer shell electrons?
Group 1, Group 2, Groups 3 – 12, Group 17, Group 18
What is the group name for Group 18?
Alkaline Earth Metals, Alkali Metals, Halogens, Transition Metals, Noble Gases

31. Practice Elements of which group are known as the Alkali Metals?
Group 1, Group 2, Groups 3 – 12, Group 17, Group 18
Elements of which group have a variable number of outer shell electrons?

32. Practice
Which scientist arranged elements in a working Periodic Table?
Galileo, Aristotle, Al-Gebbri, Mendeleev
Which property of elements is the basis for arrangement in the Periodic Table?
Atomic Mass, Boiling Point, Number of Neutrons, Chemical Properties
Which subatomic particle determines the chemical properties of an element?
Protons, Neutrons, Electrons, Quarks

33. Practice Vertical columns on the Periodic Table are
Groups, Rows, Periods, Clans
How many valence electrons would Sulfur have? (Group 16)
2, 6, 8, 16, 32
Nonmetals are located
To the left of the stair-step, On the stair-step, To the right of the stair-step, At the very bottom

34. Problems Which group on the Periodic Table are known as “Halogens”?
Group 1, Group 2, Groups 3 – 12, Group 17, Group 18
Ductile, Malleable, & solid at room temp.
Metalloids, Nonmetals, Metals, Yoda
Usually gas at room temp., brittle, dull or waxy
Metalloids, Metals, Nonmetals, Your HAIR!

35. Electronegativity ability to hold onto outer valence e-s
high electronegativity = tightly held e-s
low electronegativity = loosely held e-s

36. Electronegativity – cont’d
increases as you go from left to right across a period.
easier to give away a few [like those to the L] than to steal many [like those on the R]

37. Electronegativity – cont’d
decreases as you go down a group.
“every electron matters” – those with many can afford to lose some, those with little can’t
electrons shield the nucleons [protons & neutrons]
the farther out electrons are from the nucleus, the less tightly held they are [away from + charge]

38. Reactivity how likely or vigorously an element reacts with others
Metals:
decreases as you go from left to right across a period.
reactivity increases as you go down a group .
Why? It’s easier for those elements to get rid of electrons.

39. Reactivity – cont’d Non-Metals:
increases as you go from the left to the right across a period.
decreases as you go down the group.
Why? It’s easier for those elements to steal electrons.

40. Atomic Radius decreases as you go from left to right across a period.
attractive forces btw opposite charges (electrons outside / protons inside) cause cloud to be 'sucked' together a little tighter.

41. Atomic Radius – cont’d increases as you go down a group.
Why? Large jump in size of nucleus (p+s + n0s) each time you move from period to period down a group.
also, new E levels added when moving down periods

42. Alkali metals (not H) (1) Inner transition (1)
Gs and Ls correct (1)
Transition metals (1)
Metalloids (1)
Halogens (1)
IA, IIA, etc. labels (1)
Noble gasses (1)
Alkali metals (not H) (1)
Inner transition (1)
Alkaline earth metals (1)
Legend filled in (1)
VIIA
VIA VA
IVA
IIIA
IIA IA G L
Marks: 10
Total: 20