1. Most Important tool in chemistry.
Used to understand and predict the properties of elements
“periodic” – repeated in a pattern
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2. Periodic Law – when elements are arranged by increasing atomic number, there is a periodic repetition of their chemical and physical properties.
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3. Dmitri Mendeleev Go to slide 4 Russian chemist
Proposed the first periodic table in 1871
Arranged by increasing atomic mass
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4. Henry Moseley British physicist
Developed an arrangement similar to that of the modern periodic table in 1914
Arranged by increasing atomic number
Cleared up the inconsistencies of Mendeleev’s periodic table
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5. Solid – state of matter with its own definite shape and volume
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6. Liquid – state of matter that flows and has constant volume
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7. gas – state of matter that flows to conform to the shape of its container, and fills the entire volume of its container
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8. Metals: Lustrous (shiny) Malleable (pound into sheets)
Ductile (drawn into wires)
Good conductors (of electricity and heat)
On the left side of the stair-step on the periodic table
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9. Non-metals: Not lustrous (dull)
Poor conductors (of electricity and heat)
Physical properties (of most non-metals):
Brittle
Powdery
Solids or gases
On the right side of the stair-step on the periodic table
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10. Metalloids (a/k/a semimetals)
Have properties of both metals and non-metals
Along the stair-step line on the periodic table
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11. Groups (a/k/a Families)
Columns
Elements in each group have similar properties
Groups 1, 2, 13, 14, 15, 16, 17, and 18 are called “Main Groups” or “Representative Groups”
Elements in each main group have the same number of valence electrons
Valence electrons determine the chemical properties of the element
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12. Periods
Rows
Rows end when energy levels are filled
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13. Energy levels
Electrons in the electron cloud of an atom have different amounts of energy.
Electrons in levels close to the nucleus have less energy than electrons in energy levels farther away from the nucleus.
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14. Group 1 – Alkali Metals
Elements contain 1 valence electron in the outer energy level
Most reactive elements
Oxidation number is 1+
Softer than other metals
Do not occur naturally in elemental form
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15. Group 2 – Alkaline Earth Metals
Elements contain 2 valence electrons in outer energy level
Very reactive
Oxidation number is 2+
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16. Group 13 – Boron Group Main group name is 3A
Elements have 3 valence electrons in outer energy level
Oxidation number is 3+
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17. Group 14 – Carbon Group Main group name is 4A
Elements have 4 valence electrons in outer energy level
Contains non-metals, metalloids, and metals
Oxidation number can be 4+ or 4-
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18. Group 15 – Nitrogen Group Main group name is 5A
Elements have 5 valence electrons in outer energy level
Oxidation number is 3-
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19. Group 16 – Oxygen Family Main group name is 6A
Elements have 6 valence electrons in outer energy level
Oxidation number is 2-
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20. Group 17 – Halogens Main group name is 7A
Elements have 7 valence electrons in outer energy level
Oxidation number is 1-
Very reactive
Readily react with Group 1 metals
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21. Group 18 – Noble Gases Main group name is 8A
Complete outer energy level
Helium has 2 valence electrons
All other noble gases have 8 valence electrons
“I eight, I full”
Oxidation number is 0
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22. Transition Metals – Groups 3-12
Ductile, malleable, good conductors
Valence electrons vary
Group 11 is called the “coinage metals”
Copper (Cu)
Silver (Ag)
Gold (Au)
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23. Inner Transition Metals:
Fit within transition metals between groups 3 and 4, in periods 6 and 7
Lanthanides (atomic numbers 58-71)
Actinides (atomic numbers )
Actinides are radioactive and unstable
Rare
Do not exist in nature
Difficult to research