1. Chemistry: THE STUDY OF MATTER

2. So what is matter?

3. Matter Must have mass Must occupy space (have volume)
It is different from weight…..Why?
Must occupy space (have volume)
A measure of the quantity of matter (it is different from weight, which can be affected by gravity)
This volume can change depending on environmental conditions like pressure

4. Matter Has Density Density of a Substance = Mass Volume
See Reference Table S to compare density of elements

5. States of Matter Matter can exist in three basic states:
Solid (s), Liquid (l), Gas (g)
How are these states different from each other?

6. Can Matter be Destroyed?
Example:
When 400 grams of wood are burned only about 30 grams of ash remain.
What would you think?
What happened to the missing matter?

7. Law of Conservation of Matter
Matter cannot be created or destroyed
This was a revolutionary idea up until the 1800’s
Ex: Burn a candle, thought part of the candle just disappeared and became nothing.
But if you burn it in a closed container you can see the mass doesn’t change as it burns.
Matter isn’t being lost but changing in form!

8. Atoms are all still there they just get rearranged

9. Balanced chemical equations show the number of atoms stay the same during reactions and thus obey this law.

10. Basic Types of Matter: Elements vs. Compounds

11. Elements Made of atoms of one specific type
Cannot be broken down chemically
Have specific properties.

12. Examples of Elements

13. Where Do We Get Elements?
Obtained in nature in their pure state.

14. Found combined with other elements in compounds
Ex: Electrolysis of Water

15. Man-made through nuclear bombardment reactions

16. Elements and Their Symbols
Take Note Please!
Elements have either one or two letters when they are written as a symbol.
If two letters, the second letter is written lower case. (Ex: Write Cu for copper not CU)
Why is this so important?

17. Sometimes the symbol is derived from a Latin name for the element.
Usually it is pretty easy to match an element to its symbol (Ex: Neon = Ne)
Sometimes the symbol is derived from a Latin name for the element.
Ex: Au = gold (comes from Latin word aurum)

18. Tricky Elements Na = sodium K = potassium Fe = iron Cu = copper
Sb = antimony
Sn = tin
Pb = lead
Hg = mercury
W = tungstun
Au = gold
Ag = silver

19. Phases and Elements Solids: Gases:
Most elements are solids
Gases:
H, He, Ne, Ar, Kr, Xe, Rn, N, O, F, Cl
Liquids:
Hg, Br
Let’s make a note of these on our Periodic Tables!

20. Diatomic Elements Most elements are monoatomic in pure form.
Some elements have two atoms joined (diatomic)
Who are they?
Remember BrINClHOF
Let’s make a note of these on our Periodic Tables!

21. Compounds Two or more different elements bonded together chemically
Ex: C6H12O6, NO2, CO2, NaCl
Note: Most elements in nature do not exist in their pure state, but in compounds.
Why?
The numbers written below the symbols are called “subscripts” and let us know about the number of each type of atom in the compound

22. Law of Definite Proportions
Compounds have specific formulas that show the proportion of elements to each other.
Ex: Water is always H2O
A “mixture” has proportions that can vary
Ex: salt water
Ex: H2O always has 2
hydrogen and one
oxygen atom in it

24. Getting New Properties
Compounds have different chemical and physical properties than the elements that make them up.

25. - Sodium (Na)
Toxic metal
- Chlorine (Cl)
Toxic gas
Sodium Chloride (NaCl)
White edible crystal
salt for my french fries!!

26. Focus Question What makes atoms of one element different from another?
What is inside its atoms…

27. Atomic Basics Atoms consist of three basic parts. Protons Neutrons
Electrons

28. Fill in Chart: Particle Charge Mass Location Symbol Proton Neutron
Electron

29. Atomic Number: Tells us the number of protons in nucleus
It is unique for each element

30. Atomic Charge Atoms are neutral particles
Number of electrons (-) = number of protons (+)
How many electrons does an atom of carbon have?

31. Nuclear Charge Nuclear Charge: What is the Nuclear Charge?
the charge on the nucleus of the atom.
(+) positive charge = to number of protons
What is the Nuclear Charge?
What is the Atomic Number?
What is this Element?

32. Ionic Charge Ions: atoms with a charge Protons don’t equal electrons!!
Atom has gained or lost electrons
Gain electrons: become (-) ion
Lose electrons: become (+) ion
P = 9
E = 10
What is the element? What is it’s ionic charge?

33. Ionic Charge Practice
Try a few for practice…

34. Finding the Atom’s Mass
Mass Number:
Sum of the number of protons + neutrons
Each has a mass of 1 amu. (atomic mass unit)
Ex: P = 23 N = 21
What is the Atomic Mass Number?
What is this element?

36. Isotopes
Isotopes: atoms of the same element with different atomic mass.
Same # protons
Different # neutrons
Ex: Carbon-12, Carbon-13, Carbon-14
How many protons?
How many neutrons?

37. Average Atomic Mass: Atomic mass you see on periodic table
Represents the average mass of all the isotopes of an element in a typical sample.
Based upon abundance of each isotope and their mass

38. Calculating Average Atomic Mass
Mass of each isotope x abundance (change % abundance to decimal)
Add together answers
Ex: Chlorine

40. Crash Course: Atomic Basics