1. The Periodic Table and Elements
The Periodic Table Song

3. The Periodic Table
Dmitri Mendeleev ( )

4. Elements are arranged:
Vertically into Groups
Horizontally Into Periods

5. Why?

6. If you looked at one atom of every element in a group you would see…

7. Each atom has the same number of electrons in its outermost shell.
An example…

8. The group 2 atoms all have 2 electrons in their outer shells
Be (Beryllium)
Atom
Mg (Magnesium) Atom

9. The number of outer or “valence” electrons in an atom affects the way an atom bonds.
The way an atom bonds determines many properties of the element.
This is why elements within a group usually have similar properties.

10. If you looked at an atom from each element in a period
you would see…

11. Each atom has the same number of electron shells.
An example…

12. The period 4 atoms each have 4 electron containing shells
4th Shell
K (Potassium)
Atom
Kr (Krypton)
Atom
Fe (Iron) Atom

13. Each group has distinct properties
The periodic Table is divided into several groups based on the properties of different atoms.

14. Soft, silvery coloured metals
Group 1A: Alkali Metals
Soft, silvery coloured metals
Very reactive!!!

15. Group 1A: Alkali Metals Reaction of potassium + H2O
Cutting sodium metal

16. Alkali Metals reacting with water:
Li (Lithium) – least reactive
Na (Sodium)
K (Potassium)
Rb (Rubidium)
Cs (Cesium) – more reactive
What would you expect from Francium?!?!

17. Group 2A: Alkaline Earth Metals
Magnesium
Magnesium oxide

18. Alkaline Earth Metals
Silvery-White Metals
Fairly reactive
Many are found in rocks in the earth’s crust

19. Transition Metals
Most are good conductors of electricity
Malleable (easily bent/hammered into wires or sheets)

20. How many things can you think of that have Transition Metals in them?

22. Metalloids lie on either side of the “staircase”
They share properties with both metals and non-metals
Si (Silicon) and Ge (Germanium) are very important “semi-conductors”

23. What are semiconductors used in?

24. Nonmetals
Brittle
Do not conduct electricity

25. Halogens
Most are poisonous
Fairly reactive – react with alkali metals (eg) Na+ and Cl-

26. Chlorine Gas was used as a chemical weapon during World War I.
It was used by the Germans in World War II.

27. Chlorine Gas
The Germans were the first to use Chlorine gas at Ypres in 1915
Chlorine gas is a lung irritant
The symptoms of gas poisoning are bright red lips, and a blue face
People affected die a slow death by suffocation
Decades later men who thought they had survived the war died from lung diseases such as Emphysema

28. CHLORINE

29. Noble Gases
Unreactive
Gases at room temperature

30. Jellyfish lamps made with noble gases artist- Eric Ehlenberger

31. Colors Noble Gases produce in lamp tubes:
Ne (Neon): orange-red
Hg (Mercury): light blue
Ar (Argon): pale lavender
He (Helium): pale peach
Kr (Krypton): pale silver
Xe (Xenon): pale, deep blue

32. Lanthanide Series
Actinide Series

33. (A) Periods of the periodic table, and (B) groups of the periodic table.

34. Chemical “Groups”
IA are called alkali metals because they react with water to form an alkaline solution (basic)
They are very reactive
Group IIA are called the alkaline earth metals because they are reactive, but not as reactive as Group IA.
They are also soft metals
Group VIIA are the halogens
These need only one electron to fill their outer shell
Group VIIIA are the noble gases as they have completely filled outer shells
They are almost non-reactive.

35. Four chemical families of the periodic table: the alkali metals (IA), the alkaline earth metals (IIA), halogens (VII), and the noble gases (VIIIA).

36. Metal: Elements that are usually solids at room
temperature Most elements are metals.
Non-Metal: Elements in the upper right corner of the
periodic table. Their chemical and physical properties
are different from metals.
Metalloid: Elements that lie on a diagonal line between the metals and non-metals. Their chemical and physical properties are similar to both.

37. The Atom An atom consists of a nucleus (of protons and neutrons)
electrons in space about the nucleus.
Electron cloud
Nucleus

38. ATOM COMPOSITION The atom is mostly empty space
protons and neutrons in the nucleus.
the number of electrons is equal to the number of protons.
electrons in space around the nucleus.
extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water.

39. Compounds composed of two or more elements in a fixed ratio
properties differ from those of individual elements
EX: table salt (NaCl)

40. Composition of molecules is given by a MOLECULAR FORMULA
A MOLECULE is two or more atoms bonded together – they may be the same element (ie diatomic molecule) or they may be different elements (ie caffeine)
Composition of molecules is given by a MOLECULAR FORMULA
H2O
C8H10N4O2 - caffeine

41. ELEMENTS THAT EXIST AS DIATOMIC MOLECULES
Remember:
The “GENS”
These elements exist as PAIRS when ALONE.
Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Halogens
(F2, Cl2, Br2, I2)
(P4 and S8)

42. Isotopes
Atoms of the same element (same Z) but different mass number (A).
Boron-10 (10B) has 5 p and 5 n
Boron-11 (11B) has 5 p and 6 n
10B
11B

43. Isotopes & Their Uses
Bone scans with radioactive technetium-99.

44. CARBON-14 – RADIOACTIVE ISOTOPE
Occurs in trace amounts in the atmosphere
Absorbed into living organisms
The half-life of carbon-14 is approx years (when half the C-14 is converted to N-14)

45. Atomic Symbols sodium-23
Show the name of the element, a hyphen, and the mass number in hyphen notation
sodium-23
Show the mass number and atomic number (number of protons) in nuclear symbol form
mass number
23 Na
atomic number

46. Isotopes?
Which of the following represent isotopes of the same element?
Which element is it?
234 X X 235 X 238 X
Uranium

47. IONS
IONS are atoms or groups of atoms with a positive or negative charge.
Donating an electron from an atom gives a CATION with a positive charge
Accepting an electron to an atom gives an ANION with a negative charge
To tell the difference between an atom and an ion, look to see if there is a charge in the superscript! Examples: Na+ Ca+2 I- O-2 Na Ca I O

48. Forming Cations & Anions
A CATION forms when an atom loses one or more electrons.
An ANION forms when an atom gains one or more electrons
F + e- --> F-
Mg --> Mg e-

49. PREDICTING ION CHARGES
In general
metals (Mg) lose electrons --> cations (Mg2+)
nonmetals (F) gain electrons ---> anions (F-)

50. When an atom or molecule gain or loses an electron it becomes an ion.
A cation has lost an electron and therefore has a positive charge
An anion has gained an electron and therefore has a negative charge.

51. Charges on Common Ions -3 -2 -1 +1 +2
By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.

52. How many protons, electrons and neutrons are in an atom of krypton
Step 1 – Gather Information
Using the periodic Table find the atomic number and atomic weight

53. How many protons, electrons and neutrons are in an atom of krypton
Step 2 – The Number of Protons is …
The number of Protons = the atomic number

54. How many protons, electrons and neutrons are in an atom of krypton
Step 3 – The Number of Electrons is …
The number of Electrons = the number of Protons
Unless it is an ion

55. How many protons, electrons and neutrons are in an atom of krypton
Step 4 – The Number of Neutrons is …
Round the atomic to the nearest whole number
Subtract the number the atomic number

56. Learning Check – Counting
State the number of protons, neutrons, and electrons in each of these ions.
39 K O Ca +2
#p+ ______ ______ _______
#no ______ ______ _______
#e- ______ ______ _______ 8 20 19 20 8 21 18 10 18

57. Elements with 1, 2, or 3 electrons in their outer shell tend to lose electrons to fill their outer shell and become cations.
These are the metals which always tend to lose electrons.
Elements with 5 to 7 electrons in their outer shell tend to gain electrons to fill their outer shell and become anions.
These are the nonmetals which always tend to gain electrons.
Semiconductors (metalloids) occur at the dividing line between metals and nonmetals.

58. EXAMPLE So the charge would be +1
What would the charge be on a sodium ion?
Since sodium in in Group IA it is a metal and so would
LOSE an electron
You can tell how many would be lost by the group number
Group 1A elements lose 1 electron
So the charge would be +1
Remember an electron is negatively charged. When you lose them an atom becomes positively charged…
when you gain them it becomes negatively charged

59. Na +1 EXAMPLE It has 1…remember the group number!
How would you right the symbol for the sodium CATION? Na +1
How many outer electrons does sodium have before it loses one?
It has 1…remember the group number!