1. The most fundamental concept in
The Periodic Table
The most fundamental concept in
CHEMISTRY!

2. Dmitri Mendeleev Russian Invented periodic table
Organized elements by properties
Arranged elements by atomic mass
Predicted existence of several unknown elements
Element 101 named for him
Dmitri Ivanovich Mendeleev (1834 – 1907)
Arranged elements by increasing atomic mass. Proposed that properties of different elements repeat at regular intervals.
1860’s proposed new arrangements of elements.
1869 Published original periodic table
Dmitri Mendeleev was the Russian chemist who invented the periodic table of the elements.
He was born in Siberia and was the youngest of 17 children.
Mendeleev missed receiving the Nobel prize in chemistry by just one vote in 1906, and died before the next year’s election.
Element 101 (discovered in 1955) was named Mendelevium in his honor.
Dmitri Mendeleev

3. FYI Mendeleev’s Early Periodic Table
The ? Indicate undiscovered elements
TABELLE II
GRUPPE I GRUPPE II GRUPPE III GRUPPE IV GRUPPE V GRUPPE VI GRUPPE VII GRUPPE VIII
___ ___ ___ ___
RH RH RH RH
R2O RO R2O RO R2O RO R2O RO4
REIHEN 1 2 3 4 5 6 7 8 9 10 11 12
H = 1
Li = Be = B = C = N = O = F = 19
Na = Mg = Al = Si = P = S = Cl = 35.5 ?
K = Ca = __ = Ti = V = Cr = Mn = Fe = 56, Co = 59,
Ni = 59, Cu = 63
(Cu = 63) Zn = __ = __ = As = Se = Br = 80
Rb = Sr = ? Yt = Zr = Nb = Mo = __ = Ru = 104, Rh = 104,
Pd = 106, Ag = 108
In the 1860’s, Mendeleev and the German chemist Lothar Meyer, each working alone, made an eight-column table of the elements.
However, Mendeleev had to leave some blank spots in order to group all the elements with similar properties in the same column. To explain these blank spots, Mendeleev suggested there must be other elements that had not yet been discovered. On the basis of his arrangement, Mendeleev predicted the properties and atomic masses of several elements that were unknown at the time.
Mendeleev left blanks in his table for undiscovered elements.
Mendeleev predicted properties and masses of unknown elements correctly.
(Ag = 108) Cd = In = Sn = Sb = Te = J = 127
Cs = Ba = ? Di = ? Ce = __ __ __ __ __ __ __
( __ ) __ __ __ __ __ __
__ __ ? Er = ? La = Ta = W = __ Os = 195, Ir = 197,
Pt = 198, Au = 199
(Au = 199) Hg = Tl= Pb = Bi = __ __
__ __ __ Th = __ U = __ __ __ __ __
From Annalen der Chemie und Pharmacie, VIII, Supplementary Volume for 1872, p. 151.

4. The ? Elements’ Properties are Predicted
Property
Mendeleev’s Predictions in 1871
Observed Properties
Molar Mass
Oxide formula
Density of oxide
Solubility of oxide ?
44 g
M2O3
3.5 g / ml
Dissolves in acids
Scandium (Discovered in 1877)
43.7 g
Sc2O3
3.86 g / ml
Molar mass
Density of metal
Melting temperature
68 g
6.0 g / ml
Low
Dissolves in ammonia solution
Gallium (Discovered in 1875)
69.4 g
5.96 g / ml
30 0C
Ga2O3
Dissolves in ammonia
Color of metal
Chloride formula
Density of chloride
Boiling temperature
of chloride
72 g
5.5 g / ml
Dark gray
High
MO2
4.7 g / ml
MCl4
1.9 g / ml
Below 100 oC
Germanium (Discovered in 1886)
71.9 g
5.47 g / ml
Grayish, white
900 0C
GeO2
4.70 g / ml
GeCl4
1.89 g / ml
86 0C
Fitting in New Elements
“The crowning achievement of Mendeleyev’s periodic table lay in his prophecy of new elements. Gallium, germanium, and scandium were unknown in 1871, but Mendeleyev left spaces for them and even predicted what the atomic masses and other chemical properties would be. The first of these to be discovered in 1875, was gallium. All the characteristics fitted those he had predicted for the elements Mendeleyev called eka-aluminum – because it came below aluminum in his table.”
-Eyewitness Science “Chemistry” , Dr. Ann Newmark, DK Publishing, Inc., 1993, pg 23
In the 1860’s, Mendeleev and the German chemist Lothar Meyer, each working alone, made an eight-column table of the elements.
However, Mendeleev had to leave some blank spots in order to group all the elements with similar properties in the same column. To explain these blank spots, Mendeleev suggested there must be other elements that had not yet been discovered. On the basis of his arrangement, Mendeleev predicted the properties and atomic masses of several elements that were unknown at the time.
Mendeleev left blanks in his table for undiscovered elements.
Mendeleev predicted properties and masses of unknown elements correctly.
O’Connor Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 119,

5. Modern Periodic Table Henry G.J. Moseley
Determined the atomic numbers of elements from their X-ray spectra (1914)
Arranged elements by increasing atomic number
Look at your periodic table.
Notice how atomic mass does NOT go up between elements 27 and 28.
H.G.J. Moseley ( ) while doing post-doctoral work (with Ernest Rutherford) bombarded X-rays at atoms in increasing number and noted that the nuclear charge increased by 1 for each element. This gave him the idea to organize the elements by increasing atomic number.
Periodic law – elements organized by increasing atomic number on periodic table (1913)

6. Metals, Nonmetals, & Metalloids1 2
Nonmetals 3 4 5
Metals 6 7
Metalloids
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 349

7. Review of Properties of Metals, Nonmetals, and Metalloids
malleable,
lustrous,
ductile,
conductors of heat and electricity,
react with acid and CuCl2
Brittle,
dull,
poor conductors of heat and electricity,
do not react with acids or CuCl2
METALLOIDS
(Semi-metals)
Can have properties of both metals and non-metals.
(used in computer chips)

8. Diagram of an Atom

9. Vertical Columns are called Groups or Families.
Elements of the same group have similar properties and
behave alike chemically.
Why is this??

10. Valence Electrons Electrons on the outermost shell of an atom
Participate in bonding and determine how an element will bond when making compounds
Electrons on outside shell are valence electron; oxygen has 6
Oxygen Atom

11. Pattern for Counting Valence Electrons
Ignore the ‘1’
Only 2

12. The Families of The Periodic Table
Noble
gases
Alkaline
earth metals
Halogens 1 18 H 1 He 2 2 13 14 15 16 17 Li 3 Be 4 B 5 C 6 N 7 O 8 F 9 Ne 10 Na 11 Mg 12 3 4 5 6 7 8 9 10 11 12 Al 13 Si 14 P 15 S 16 Cl 17 Ar 18
Click on
this to
see Alkali
metals
In action!!
Transition metals K 19 Ca 20 Sc 21 Ti 22 V 23 Cr 24 Mn 25 Fe 26 Co 27 Ni 28 Cu 29 Zn 30 Ga 31 Ge 32 As 33 Se 34 Br 35 Kr 36
Alkali metals Rb 37 Sr 38 Y 39 Zr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48 In 49 Sn 50 Sb 51 Te 52 I 53 Xe 54 Cs 55 Ba 56 * Hf 72 Ta 73 W 74 Re 75 Os 76 Ir 77 Pt 78 Au 79 Hg 80 Tl 81 Pb 82 Bi 83 Po 84 At 85 Rn 86 Fr 87 Ra 88 Y Rf
104 Db
105 Sg
106 Bh
107 Hs
108 Mt
109
Uun
110
Uuu
111
Uub
112
Uuq
113
Uuh
116
Uuo
118
* Lanthanides La 57 Ce 58 Pr 59 Nd 60 Pm 61 Sm 62 Eu 63 Gd 64 Tb 65 Dy 66 Ho 67 Er 68 Tm 69 Yb 70 Lu 71
Y Actinides Ac 89 Th 90 Pa 91 U 92 Np 93 Pu 94 Am 95 Cm 96 Bk 97 Cf 98 Es 99 Fm
100 Md
101 No
102 Lr
103

13. Practice the information just learned by
completing the Homework on packet page 31

14. Horizontal Rows are called Periods.
The Period number tells how many energy levels, or shells, an element has.
LABEL the periods 1-7 on your periodic table.

15. Hide and Seek!
Find the element that has 3 energy levels and is a member of the Halogen family.
Chlorine
Find the element that has 2 valence electrons and 3 energy levels.
Magnesium

16. Let’s blow up Carbon to have a better look at what information is there
Atomic number
(tells # of protons
and electrons in a
Neutral atom)
Element name
Element symbol
Atomic mass
“Atomic mass” is the
average mass number of all the Carbon atoms on Earth.

17. Isotope Atoms of the same element with different number of neutrons.
Isotopes of an element will have different masses.
Ex: two isotopes of carbon
Carbon-12 has a mass of 12
Carbon-14 has a mass of 14

18. Protons have a mass = 1 amu
Neutrons have a mass = 1 amu
Electrons have a negligible mass
How do you calculate the mass of an atom?
Mass number = protons + neutrons

19. Try These An atom of nitrogen has 8 neutrons. What is its mass number?15
A uranium atom has a mass number of How many neutrons does it have?
143
An element has a mass number of 56 and 30 neutrons. What element is it?
iron

20. There isn’t a “regular” carbon here; there are two isotopes
There isn’t a “regular” carbon here; there are two isotopes. The two symbols shown below & right are called “isotopic symbols”.

21. Isotopic Symbol
Represents mass number 12 C 6
Represents Atomic Number

22. Your Turn
Write the isotopic symbol for an isotope of Calcium that has 21 neutrons. 41 Ca 20
How many protons does this isotope have?
How many electrons does this isotope have?
How many neutrons does this isotope have? 20 20 21

23. Isotopes of Boron Boron-10 and Boron-11
Which is more abundant (meaning more of
it naturally exists)?
There must be more Boron-11 if the average mass is

24. Practice the information just learned by
completing the Homework on packet page 35
and 37.
Note! On p 37, do not do #4,6 and 9 until later!!!

25. So, Atoms Can Change!
Changing different parts of the atom may or may not change it’s behavior
What happens if we change the number of protons in an atom?
You change the element
An atom with 12 protons is…
Magnesium
Add a proton, atom is now…
Aluminum
(changing number of protons is not common)

26. What happens if you change the number of neutrons in an atom?
You change the isotope (or form of the atom)

27. What happens if you change the number of electrons in an atom?
You create an ion!....
Wait what is that?
When an atom gains or loses electrons
and therefore is no longer neutral.

28. Atoms vs. Ions
Atoms can gain or lose valence electrons. Once they do, they are called IONS.
Why become an ion?
in order to achieve a full outer energy level (or full octet) like the noble gases
A full energy level has less energy, and therefore is more stable.
Ions can ‘bond’ to form compounds- Ionic bonds

29. A Negatively Charged Ion is called
Anion
(pronounced: ‘an-eye-on”)
Example: Cl-

30. Example of an anion
Cl (atom) has 17 positive protons and 17 negative electrons
(17 protons)
(17 electrons)
Atom is neutral because it has equal numbers of
protons and electrons.
What if a chlorine atom gained an electron?
There is now one more electron!
This makes for a total -1 charge.
We now have a chloride ion
17 protons
18 electrons

31. A Positively Charged Ion is called
Cation
(pronounced: ‘cat-eye-on’)
Example: Na+

32. Example of a cation
Na (atom) has 11 positive protons and 11 negative electrons
(11 protons)
(11 electrons)
Atom is neutral because it has equal numbers of
protons and electrons.
What if a sodium atom lost an electron?
There is now one more proton!
This makes for a total +1 charge.
We now have a sodium ion
11 protons
10 electrons

33. Ions
Remember, atoms try to achieve a full outer energy level by gaining or losing valence electrons.
This is known as the octet rule…most atoms try to get 8 electrons in their outer level.
EXCEPTION! If there is only one energy level, a full energy level is only two electrons.
Atoms always do what is easier to get to the full octet!

34. Formation of an ion.
Sodium is not happy having just one valence electron.
It wants to have a full outer shell
It could either gain 7 more electrons to have a full third level
Or it could lose 1 electron and have a full second level
Which do you think it will do?
sodium atom Na e- e- e- e- e- e-
11p+ e- e- e- e- e- e-

35. It is easier to lose one electron It will NEVER gain 7!
sodium atom Na
sodium ion
11p+ e- e- e- e- e- e- e-
loss of
one valence
electron
to attain a
full outer
energy level
11p+ e- e- e- e- e- e-
Because Na lost one electron, it has a +1 charge.
It has become the Na+ ion.

36. Formation of an ion
Chlorine is not happy having only 7 valence electrons.
It wants to have a full outer shell
It could either gain 1 more electron to have a full third level
Or it could lose 7 electrons and have a full second level
Which do you think it will do?
chlorine atom Cl e- e- e- e- e- e- e-
17p+ e- e- e- e- e- e- e- e- e- e-

37. It is easier to gain 1 electron It will NEVER lose 7!
chlorine atom Cl
chloride ion
17p+ e- e- e- e- e- e- e- e-
gain of
one valence
electron
to attain a
full outer
energy level e-
17p+ e- e- e- e- e- e- e- e- e- e-
Because Cl gained one electron, it has a -1 charge.
It has become the Cl- ion.

38. First 18 elements:
Energy levels drawn, showing valence electrons
Number of valence electrons written above familes
Notice the exception for Helium

39. +1 -3 +2 -2 -1 Number of valence electrons
Lose 1 xx xx
Gain3
FULL
Lose 2
Gain 2 +1
Gain 1 -3 +2
How many electrons will each family gain or
lose to get a full outer energy level?
What charge will each family’s ions be? -2 -1

40. Determine Charge of the Following Ions
Sodium Ion +1
Fluoride Ion -1
Bromide Ion
Calcium Ion +2
Copper Ion
Depends on what it is bonded with

41. Exceptions to Ion Charge Pattern
Ag is always +1
Zinc is always +2
Aluminum is always +3

42. Now write an isotopic symbol for a chlorine ion with a mass number of 37.
Cl- 17 17
How many protons does this isotope have?
How many electrons does this isotope have?
How many neutrons does this isotope have? 18 20

43. Begin Homework! Finish Isotope worksheet, pkt p 37 #4,6 and 9
Complete Ions worksheet, pkt p 41
Read and take notes on Book section B.10 found on p Put notes on pkt p 40.