1. PHYSICAL SCIENCE CHAPTER 5
THE PERIODIC TABLE

2. ORGANIZING THE ELEMENTS
SECTION 1
ORGANIZING THE ELEMENTS

3. ORGANIZING THE ELEMENTS
Lavoisier grouped known elements into 4 MAJOR CATEGORIES: metals, non-metals, gases, and earths.

4. MENDELEEV’S PERIODIC TABLE
Looking for the best way to organize the elements.
HE PROPOSED: that elements with similar properties could be lined up in rows based on increasing mass
HIS PREDICTION: that he could use the elements on the table to predict the properties of elements still missing from the table.
EVIDENCE: Gallium and Eka-aluminum are considered same element because they are so similar

5. THE MODERN PERIODIC TABLE
SECTION 2
THE MODERN PERIODIC TABLE

6. MODERN PERIODIC TABLE
PERIODIC LAW: elements are arranged by increasing atomic number (# of protons)
PERIODS: each row in the table is a period and the number of elements per period varies due to number of available orbitals per energy level
GROUPS: each column in the table is a group
Properties of elements repeat in a predictable way when atomic numbers are used to arrange elements into groups (families).

7. ATOMIC MASS
ATOMIC MASS IS A VALUE THAT DEPENDS ON THE DISTRIBUTION OF AN ELEMENT’S ISOTOPES IN NATURE AND THE MASSES OF THOSE ISOTOPES.
ATOMIC MASS UNITS: is defined as one twelfth of the mass of a carbon-12 atom

8. CLASSES OF ELEMENTS
ELEMENTS ARE CLASSIFIED AS METALS, NON-METALS, AND METALLOIDS.
METALS: good conductors of electricity and heat, most are malleable, many are ductile (can be drawn into wire)
NON-METALS: poor conductors of electricity or heat, have low boiling points, tend to be gas at room temperature
METALLOIDS: have properties of metals and non-metals: good insulator at low temps, good conductor at high temps.

9. VARIATION ACROSS A PERIOD
ACROSS A PERIOD FROM LEFT TO RIGHT, THE ELEMENTS BECOME MORE NON-METALLIC IN THEIR PROPERTIES
THEY ALSO DECREASE IN REACTIVITY FROM LEFT TO RIGHT

10. REPRESENTATIVE GROUPS
SECTION 3
REPRESENTATIVE GROUPS

11. REPRESENATATIVE GROUPS
A valence electron: is an electron that is in the highest occupied energy level of an atom
STABLE OR NOT?
Play a key role in chemical reactions
Elemental properties vary across a period because the number of valence electrons increases from left to right
Elements in a group have similar properties because they have same number of valence electrons.

12. GROUP 1A: ALKALI METALS Single valence electron, extremely reactive
Found only in compounds
The reactivity of alkali metals increases from the top to bottom of group 1A.

13. GROUP 2A: ALKALINE EARTH METALS
2 valence electrons, harder than metals in group 1A
Differences in reactivity of alkaline earth metals is shown in how they react with water.
magnesium: when mixed with other metals can be as hard as steel but lighter…bicycle frames
Calcium: your body needs it for bones and teeth, Calcium Carbonate (mixture of calcium, carbon and oxygen) is main ingredient in chalk and limestone.

14. GROUP 3A: BORON FAMILY All elements in 3A have 3 valence electrons
This group is made up of two different types of elements: metals and metalloids

15. GROUP 4A: CARBON FAMILY Contains 4 valence electrons
1 non-metal=carbon
2 metalloids = silicon and germanium
2 metals = tin and lead
Except for water, most of the compounds in your body contain carbon.

16. GROUP 5A: NITROGEN FAMILY
Each element in this family has 5 valence electrons
2 non-metals = nitrogen (gas) and phosphorus(solid)
2 metalloids = arsenic and antimony
1 metal = bismuth
BESIDES NITROGEN, FERTILIZERS OFTEN CONTAIN PHOSPHORUS.

17. GROUP 6A: OXYGEN FAMILY
OXYGEN IS MOST ABUNDANT ELEMENT IN EARTH’S CRUST
3 non-metals = oxygen, sulfur, and selenium
2 metalloids = tellurium and polonium
ALL ELEMENTS IN THIS GROUP HAVE 6 VALENCE ELECTRONS

18. GROUP 7A: HALOGENS HAS 7 VALENCE ELECTRONS
DESPITE PHYSICAL DIFFERENCES, HALOGENS HAVE SIMILAR CHEMICAL PROPERTIES
HIGHLY reactive non-metals…fluorine most reactive

19. GROUP 8A: NOBLE GASES Group has 8 valence electrons
Noble gases are colorless and odorless, also very non-reactive
Very hard to detect