1. Topic 3: Elements & the Periodic Table

2. Organizing the Elements
Meet the Elements
Elements are organized based on their physical and chemical properties

3. Each element was named and given a symbol
Berzelius (1814)
Used letters to represent the element
First letter of name, capitalized
For elements with the same first letters – add second letter
Hydrogen (H), Helium (He), Carbon (C), Cobalt (Co)

4. Exceptions…
Some names are based on Latin names
Original elements
Gold (Au) – aurum
Iron (Fe) – ferrum
Lead (Pb) – plumbum
Copper (Cu) - cuprum

5. An Order for the Elements
Mendeleev
All elements have an atomic mass
Mass of one atom
Determined mass of each atom by comparing it with the mass of a carbon atom

6. Elements were organized by listing them in order of increasing atomic mass
Eg. Oxygen has more mass than carbon – it comes after carbon
Other properties repeat at regular intervals

8. The Periodic Table: How to Read the Elemental Road Map
A) Landmarks for each element
Name
2. Symbol

9. 3. Atomic mass
Mass of one atom of the element
Total mass of PROTONS and NEUTRONS
Electrons have essentially no mass
Is an average
Can be a difference in # of neutrons from atom to atom (isotopes)
Usually found below symbol
Eg. C = Cr =
O = Pb =
S = Ca =

10. 4. Atomic number Number of PROTONS in the nucleus of the atom
Usually found above symbol
Eg. O = C =
N = Ca =
Fe = B =

11. What pattern do you see in with respect to atomic number?
As you read left to right, atomic number increases
ATOMS are NEUTRAL
Number of protons = number of electrons
Charge balances to 0

12. # Neutrons = Atomic mass – Atomic Number
Using the atomic mass and atomic number you can determine the number of neutrons in any atom
# Neutrons = Atomic mass – Atomic Number
(Round to the nearest whole #)
Eg. Silver
Atomic mass =
Atomic number =
# Neutrons =
Eg. Strontium

13. Use the periodic table to find complete the table below
Symbol
Name
Atomic #
Atomic Mass
# Protons
# Electrons Ba
Nickel P 35 12
Uranium 54

14. The Periodic Table: How to Read the Elemental Road Map
Subdivisions of the map
Metals
Non-metals
Metalloids

15. Metals
Found on LEFT side of periodic table
Similar physical properties:
Shiny, malleable, ductile, conduct heat & electricity
All are room tempEXCEPT mercury (Hg) - liquid

16. Non-metals
Found on RIGHT side of table
Similar physical properties:
Dull, brittle, insulators (don’t conduct heat or electricity)
At room temperature - some gases, some solids; ONLY liquid is bromine (Br)

17. Metalloids
“Dividing line” between metals and non-metals
Both metallic and non-metallic properties
Shiny or dull, may conduct electricity, poor conductors of heat, brittle, not ductile
All solids at room temperature
Atomic #s: 5 14 32 33 51 52 84

18. The Periodic Table: How to Read the Elemental Road Map
C) Neighborhoods
1. Families (Groups)
Vertical columns
#1-18 (L to R)
Have similar chemical properties
Reactivity increases as you move down the group

19. Group 1 = Alkali metals
Have 1 electron in outer shell
Most reactive metals – react when exposed to air and water

20. Group 2 = Alkaline earth metals
Have 2 electrons in outer shell
Reactive

21. Groups 3 – 12 – Transition Metals

22. Group 17 = Halogens
Have 7 electrons in outer shell
Most reactive non-metals

23. Group 18 = Nobel gases
Have 8 electrons in outer shell (no unpaired electrons)
Most stable elements
Unreactive

24. 2. Periods
Horizontal rows
# 1 – 7 from top to bottom