1. The Periodic Table!

2. Important People to Remember
Dmitri Mendeleev
- published 1st periodic table in 1869
- arranged elements by atomic mass

3. Important People to Remember
Henry Moseley
- arranged the periodic table for today
- arranged elements by atomic number

4. Groups and Periods On the periodic table:
Elements are arranged according to similar properties.
Periods
Groups
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5. Metals, Nonmetals, and Metalloids
The heavy zigzag line
separates metals and
nonmetals.
Metals are located to the left.
Nonmetals are located to the right.
Metalloids are located along the heavy zigzag line between the metals and nonmetals.
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

6. Metals To the left of the Zigzag Malleable (smashed into thin sheets)
Ductile (stretched into wires)
Conduct heat and electricity
Shiny
Reactive
High Melting Points
Mostly Solids at room temperature
- except Hg (liquid)

7. Examples of Metals Fe

8. Non-Metals Right of the zigzag (Upper right side)
Poor conductor of electricity
Dull
Brittle
Low Melting Points
Mostly gases at room temperature
Liquid (Bromine)
Solids (Sulfur, Phosphorus, Carbon)

9. Examples of Nonmetals
Sulfur
Carbon

10. Metalloids Along the zigzag line!
Has properties of both metals AND nonmetals!
Somewhat shiny solids, not much luster
Semiconductive
B, Si, Ge, As, Sb, Te, Po, At

11. Examples of Metalloids
Silicon

12. Names of Some Representative Elements
Several groups of representative elements are known by common names.
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

13. Alkali Metals Group 1: Li, Na, K, Rb, Cs, Fr VERY reactive Soft Metals
Rarely exist in nature alone
Form salts when combined

14. Alkaline Earth Metals Group 2: Be, Mg, Ca, Sr, Ba, Ra Reactive
Found in compounds that are in the Earth’s Crust
More dense and harder than alkali metals

15. Transition Metals In the middle (d-block) Much LESS reactive
Electron in highest energy level can change
Therefore when they form ions, their charges can vary.

16. Examples:
Cu+2
Cu+1

17. Halogens Group 7: F, Cl, Br, I, At Most reactive non metals
Fluorine most reactive non metal
Physical properties very within group

18. Noble Gases Group 8: He, Ne, Ar, Kr, Xe, Rn
Don’t react or combine with anyone! (Unless forced) INERT GASES
Low Boiling Points
All gases at room temperture

19. Lanthanides Elements 58-71 - All occur in nature except 61
Rare earth metals
Very reactive
High melting points and boiling points
Used in lamps, lasers, magnets, and motion picture projectors.

20. Actinides Elements 90-103 Most are synthetic (man-made)
Almost all are radio active
Very dense
Can be found in smoke detectors, nuclear weapons, and radio active minerals

21. Periodic Law
Periodic Law = trends that occur throughout the periodic table
-Atomic Radius
-Ionization Energy
-Electronegativity

22. How are the elements organized?
Atoms in the same group have the same number of valence electrons.
Outer shell = valence shell (outside electrons)
8 valence electrons= stable
Valence electrons determine reactivity and how strongly an atom will bond with other atoms.

23. Determine Valence Electrons
These atoms want 8 valence electrons
- Is it easier for them to gain or lose a certain amount of electrons?

24. Atomic Radius Trend What is atomic radius?
- Distance from the nucleus to the valence electrons
- It’s the size of the atom!

25. Atomic Radius
-As you go across the period what happens to the atomic radius?
-As you go down a group what happens to the atomic radius?

26. Atomic Radius Trend More attractions = SMALL atomic radius
As you go across a period, the number of protons increases (e- increase too, but on the same energy level). More p+ can pull in e- closer, decreasing the radius.
More attractions = SMALL atomic radius
As you go down a group, e- are added to new energy levels. Each level is further from the nucleus, which increases the radius.
More energy levels = LARGE atomic radius

27. Electronegativity
Electronegativity is the atom’s want to gain electrons
An atoms LOVE for electrons!!

28. Electronegativity What happens when you go across a period?
Down a group?

29. Electronegativity
As you go across a period, electrons are held more closely because the atomic radius decreases. It is easier to attract electrons, so electronegativity increases.
Small radius (more attractions) = HIGH electronegativity
As you move down a group, electrons are further away from nucleus because the atomic radius increases. It is harder to attract electrons, so electronegativity decreases.
Large radius (less attractions) = LOW electronegativity

30. Electronegativity Look at the dot structures!
The atom that wants to GAIN electrons will have a high electronegativity!

31. Ionization energy
Ionization Energy is the energy needed to remove a valence electron
-What do see as you go across the period?
-What happens to the energy going down a group?

32. Ionization energy
•As you go across a period, electrons are held more closely because the atomic radius decreases. It is easier to attract electrons, so electronegativity increases.
Small radius (more attractions) = HIGH ionization energy
As you go down a group, electrons are further from nucleus because the atomic radius increases. It takes less energy to remove an electron, so the ionization energy decreases.
Large radius (less attractions) = LOW ionization energy
You can also look at the dot structures!