1. Elements, Compounds, and Mixtures

2. What is an ELEMENT? A substance composed of a single kind of atom.
Cannot be broken down into another substance by chemical or physical means.

3. What is a COMPOUND?
A substance in which two or more different elements are CHEMICALLY bonded together.

4. What is a MIXTURE?
Two or more substances that are mixed together but are NOT chemically bonded.

5. Element, Compound or Mixture?

6. Element, Compound or Mixture?

7. Element, Compound or Mixture?

8. Element, Compound or Mixture?

9. Element, Compound or Mixture?

10. Element, Compound or Mixture?

11. The Periodic Table
Chapter 6

12. Why is the Periodic Table important to me?
The periodic table is the most useful tool to a chemist.
It organizes lots of information about all the known elements.

13. Pre-Periodic Table Chemistry …
…was a mess!!!
No organization of elements.
Imagine going to a grocery store with no organization!!
Difficult to find information.
Chemistry didn’t make sense.

14. Dmitri Mendeleev: Father of the Table
HOW HIS WORKED…
Put elements in rows by increasing atomic weight.
Put elements in columns by the way they reacted.
SOME PROBLEMS…
He left blank spaces for what he said were undiscovered elements. (Turned out he was right!)
He broke the pattern of increasing atomic weight to keep similar reacting elements together.

15. I made the PERIODIC TABLE !
I am Dmitri Mendeleev!
I made the PERIODIC TABLE !

16. How do you read the PERIODIC TABLE?

17. What is the ATOMIC NUMBER?
The number of protons found in the nucleus of an atom Or
The number of electrons surrounding the nucleus of an atom.

18. What is the SYMBOL?
An abbreviation of the element name.

19. What is the ATOMIC MASS?
The number of protons and neutrons in the nucleus of an atom.

20. How do I find the number of protons, electrons, and neutrons in an element using the periodic table?
# of PROTONS = ATOMIC NUMBER
# of ELECTRONS = ATOMIC NUMBER
# of NEUTRONS = ATOMIC _ ATOMIC
MASS NUMBER

21. The Current Periodic Table
Mendeleev wasn’t too far off.
Now the elements are put in rows by increasing ATOMIC NUMBER!!
The horizontal rows are called periods and are labeled from 1 to 7.
The vertical columns are called groups are labeled from 1 to 18.

22. Rows

23. Groups

24. Groups…Here’s Where the Periodic Table Gets Useful!!
Elements in the same group have similar chemical and physical properties!!
(Mendeleev did that on purpose.)

26. Properties of Metals
Metals are good conductors of heat and electricity.
Metals are shiny.
Metals are ductile (can be stretched into thin wires).
Metals are malleable (can be pounded into thin sheets).
A chemical property of metal is its reaction with water which results in corrosion.

27. Properties of Non-Metals
Non-metals are poor conductors of heat and electricity.
Non-metals are not ductile or malleable.
Solid non-metals are brittle and break easily.
They are dull.
Many non-metals are gases.
Sulfur

28. Properties of Metalloids
Metalloids (metal-like) have properties of both metals and non-metals.
They are solids that can be shiny or dull.
They conduct heat and electricity better than non-metals but not as well as metals.
They are ductile and malleable.
Silicon

29. Families on the Periodic Table
Columns are also grouped into families.
Families may be one column, or several columns put together.
Families have names rather than numbers. (Just like your family has a common last name.)

31. Hydrogen Hydrogen belongs to a family of its own.
Hydrogen is a diatomic, reactive gas.
Hydrogen was involved in the explosion of the Hindenberg.
Hydrogen is promising as an alternative fuel source for automobiles

33. Alkali Metals
1st column on the periodic table (Group 1) not including hydrogen.
Very reactive metals, always combined with something else in nature (like in salt).
Soft enough to cut with a butter knife

35. Alkaline Earth Metals Second column on the periodic table. (Group 2)
Reactive metals that are always combined with nonmetals in nature.
Several of these elements are important mineral nutrients (such as Mg and Ca

37. Transition Metals Elements in groups 3-12 Less reactive harder metals
Includes metals used in jewelry and construction.
Metals used “as metal.”

39. Boron Family Elements in group 13
Aluminum metal was once rare and expensive, not a “disposable metal.”

41. Carbon Family Elements in group 14
Contains elements important to life and computers.
Carbon is the basis for an entire branch of chemistry.
Silicon and Germanium are important semiconductors.

43. Nitrogen Family Elements in group 15
Nitrogen makes up over ¾ of the atmosphere.
Nitrogen and phosphorus are both important in living things.
Most of the world’s nitrogen is not available to living things.
The red stuff on the tip of matches is phosphorus.

45. Oxygen Family or Chalcogens
Elements in group 16
Oxygen is necessary for respiration.
Many things that stink, contain sulfur (rotten eggs, garlic, skunks,etc.)

47. Halogens Elements in group 17
Very reactive, volatile, diatomic, nonmetals
Always found combined with other element in nature .
Used as disinfectants and to strengthen teeth.

49. The Noble Gases

50. The Noble Gases Elements in group 18 VERY unreactive, monatomic gases
Used in lighted “neon” signs
Used in blimps to fix the Hindenberg problem.
Have a full valence shell.