1. True Science!

2. Do you see a pattern?

3. The Periodic Table History Dmitri Mendeleev (1834-1907)
Mendeleev struggled to find some order
in the 63 elements that were known at that
time. Working with cards that he made showing
the properties of the elements he realized that
there were properties that repeated as the
atomic mass increased. The properties seem
to repeat every 8th element. He formed a table
that showed this observation:

4. Mendeleev noted patterns in the combining ratios of elements
The Elements Lithium (Li), Sodium (na), and Potassium (K) all bound with oxygen in the ratio of two atoms per oxygen atom: R2O
The Elements Beryllium (Be), Magnesium (Mg), and Calcium (Ca) all bound with oxygen in the ratio of one atom per oxygen atom: RO
Boron (B) and Aluminum (Al) form R2O3
Carbon (C) and Silicon (Si) formed RO2
Oxygen
Oxygen
Oxygen
Oxygen
Oxygen
Oxygen

5. This is
Mendeleev's
rough draft
of the first
periodic table

6. When arranged in order of their atomic mass
the elements repeat their properties
every 8th element

8. low C
middle C
high C

9. observation of repeating properties
He called the
observation of repeating properties
The "Periodic Law"
These elements showed
repeating properties

10. From the gaps present in his table, Mendeleev predicted the existence unknown elements which he called
eka-silicon
eka-boron
eka-aluminum
The elements
gallium
scandium
germanium were found later to fit his predictions quite well.

11. Electron Configuration
Trends in the
Periodic Table
Electron Configuration
In the Periodic Table

12. Why did the elements
repeat properties
every 8th element?

13. Order of Energy (filling)1 2 3 5 4 6 7 8 10 11 9 12 14 15 16 13 17
Order of Energy (filling)

14. p-orbitals 2 3 4 5 6 7 8 These elements have one or two
There are 8 columns in the periodic table that repeat the same number of valence electrons
p-orbitals 2 1 3 4 5 6 7 8
s-orbitals
These elements
have one or two
valence electrons

15. according to ATOMIC NUMBER
The table is arranged
according to ATOMIC NUMBER
From #1 to #116

16. The Periodic Table is
composed of
Groups…..(18 of these)

17. And Periods…..(7 of these)

18. Classifying the Elements
Trends in the
Periodic Table
Classifying the Elements

19. Alkali Metals Special Chemical Families
Link to website showing special families of elements

20. Alkaline Earth Metals Special Chemical Families
Link to website showing special families of elements

21. Halogens Special Chemical Families
Link to website showing special families of elements

22. Noble Gases Special Chemical Families
Link to website showing special families of elements

23. Oxygen family Special Chemical Families
Link to website showing special families of elements

24. Nitrogen family Special Chemical Families
Link to website showing special families of elements

25. Trends in the
Periodic Table
Trend #1
Metallic Properties

26. Metallic Properties More metallic
Movie Clip on Metalic trends in table
Metallic Properties
More metallic

27. Metallic Properties
Less metallic

28. Metallic Properties Very NON-metallic Very metallic Click on the Table
to bring up the
website
Metallic Properties
Very NON-metallic
Very metallic

29. Trends in the
Periodic Table
Trend #2
Atomic Size

30. Atomic Size (radius) smaller bigger “Neutral” atom with the same
number of protons as electrons
smaller
bigger

31. Why do the elements get smaller as you
go right even though they are actually getting heavier?
Answer: As they get heavier they have more protons which
pull the oppositely charged electrons IN tighter and tighter.

33. They get bigger as you go down because
you are adding more layers of electrons.

34. Trends in the
Periodic Table
Trend #3
Ionization Energy

35. electron
Ionization Energy
The Energy required to
LOSE electrons

36. Metals tend to LOSE electrons

37. Non-metals tend to GAIN electrons

38. LOST or GAINED an lectron
Ion.... An Atom that has
LOST or GAINED an lectron
or electrons
3s1
2s22p6
1s2
The illustration shows Sodium losing
an electron and becoming positively
charged. It loses the 3s1 electron.
Sodium ions always have a +1 charge +1

39. 11 protons
11 electrons
17 protons
17 electrons
17 protons
18 electrons
11 protons
10 electrons

40. Ions of Sodium
and Chlorine

41. Some elements lose or gain two or more electrons
Oxygen gains 2 electrons
Magnesium
loses 2 electrons

42. Ionization Energy
The energy needed to pull an electron off of an atom
2s22p6
3s1
1s2 +1

43. Sizes of ATOMS and their IONS The purple atoms are the NEUTRAL atoms
The Red atoms are the POSITIVE ions
The Blue atoms are the NEGATIVE ions

44. Trends in the
Periodic Table
Trend #4
Electronegativity

45. Electronegativity
The ability of an
atom to ATTRACT
electrons

46. Electronegativity How hard does an atom pull an electron
toward itself?
Electronegativity
( also called ELECTRON
AFFINITY)

49. SUMMARY of some of the trends in the periodic table