1. Intro to Chemistry

3. Periodic Table tidbits
Period table organization – organized by increasing atomic number
Split into metals (left side of stair step line) and nonmetals (right side of stair step line)
ONE EXCEPTION
Hydrogen!
vertical columns (#1-18)
Groups
horizontal rows (#1-7)
Periods

5. Atomic Structure Nucleus- center of an atom -contains protons
(which are positive)
-contains neutrons (which are neutral)
Ex- Sodium:

6. Atomic Structure Outside the Nucleus:
Electrons (which are negative) surround the nucleus in energy levels
1st energy level = holds 2e
2nd energy level = holds 8e
3rd energy level = holds 18e
4th energy level = holds 32e

7. Subatomic Particles Organized
Charge
Location
Mass
Protons
Neutrons
Electrons

8. Try it out! Read pp 104-108 then do #3, 4, 5 on page 110

9. Subatomic Particle Organized
Charge
Location
Mass
Protons
Positive
In nucleus
1 amu
Neutrons
Neutral
Electrons
Negative
Outside of nucleus/ in energy levels
0 amu
Atomic
Mass

10. An atom is defined by the number of PROTONS IT HAS!!!

11. Chemistry tidbits
Chemical Symbol- letter representing the atom (sometimes from Latin)

12. Chemistry tidbits Atomic number = number of protons
Don’t kill anyone in my class today!
Mass number = # protons + # neutrons
Don’t bother to weigh the air inside the box
So how can you calculate NEUTRONS??

13. Calculating Neutrons is a simple algebraic problem…
Atomic Mass = protons + neutrons
Atomic Number = protons
Write the equation…
Atomic Mass= Atomic Number + neutrons
#Neutrons = (mass number – atomic number)

14. Chemistry tidbits Usually can assume:
OK to round atomic mass to nearest whole number
# protons = # electrons
ONLY true for NEUTRAL ATOMS!

15. And remember…
Don’t mess with the
PROTONS!!!

16. So what CAN we “mess with?”
Neutrons…
Changes the MASS
Get an ISOTOPE
Electrons…
Changes the CHARGE
Get an ION

17. Atomic Mass Mystery…
Look at the atomic mass for Oxygen. What does it say (exactly?)
What is the atomic mass?
P + N
So what the heck!?!?!
Average of the actual isotopes on Earth!!!

18. Isotopes
Isotopes are different atoms of the same element that contain the same number of protons but different number of neutrons.
Examples
Cl vs. Cl-37
17P P
18N N

19. How to write isotopes… Mass/Hyphen Notation:
Especially important for a form of the isotope that is NOT the “usual”
Write the symbol, a dash, and the mass # for that isotope
Ex’s
C-14
C-12

20. How to write isotopes… C Nuclear Symbol Notation
Includes the symbol, atomic #, and the mass # for that isotope
Ex’s 14 6 C

21. What else CAN we “mess with?”
Neutrons…
Get an ISOTOPE
Electrons…
Get an ION

22. IONS
If you mess with the electrons you change the overall charge of the atom…an atom that is no longer neutral is called an ION.

23. Intro to Ions

24. How are these ions made? Can you mess with protons?
Would messing with neutrons do anything to the charge?
What must you mess with???
What charge does an electron have?
So what would happen to the atom if they LOSE one? Would they get more positive or more negative overall???

25. IONS
If you mess with the electrons you change the overall charge of the atom…an atom that is no longer neutral is called an ION.
ANION- has a negative charge
Means you added an electron!
CATION- has a positive charge
Means you lost an electron

26. Let’s look at our families- What ion will each form?
It all starts with the noble gases…
Everyone wants to be NOBLE

27. These are the “magic numbers”
Each of these atomic numbers will make a “full outer shell”
Other families will lose or gain electrons to get the these “numbers”

28. Alkali Metals
All (except hydrogen- of course) will lose one electron to form a __________ charge.
(+1)

29. Alkaline Earth Metals
All will lose two electrons to form a __________ charge.
(+2)
Ex-
A neutral Mg atom has 12 protons and 12 electrons (+12) + (-12) = 0
A Mg ion has 12 protons and only 10 electrons
(+12) + (-10) = +2

30. Boron Family
All will lose three electron to form a ____ charge.
(+3)

31. Nitrogen Family is special
All have four valence electrons, so it can lose four OR gain four to fulfill its octet!
So it can form a _____ or a ______ion!
-(+4) or (-4)

32. Oxygen Family All will gain two electrons to form a __________ charge.
(-2)
Ex-
A neutral Oxygen atom has 8 protons and 8 electrons
(+8) + (-8) = 0
An Oxygen ion has 8 protons and 10 electrons
(+8) + (-10) = (-2)

33. HALOGENS
All will gain one electrons to form a __________ charge.
(-1)

34. How about those noble gases?
They will NOT FORM IONS!!!

35. Let’s look at our families- What ion will each form?
It all starts with the noble gases…
Everyone wants to be NOBLE

36. How do we Draw Atoms
Bohr Models
Lewis Dot Structures

37. Look at the many things in your classroom or at home: desks, chairs, windows, shoes, etc. If all of these things are made from atoms and all atoms are made of only a few kinds of particles, what accounts for the variety of things that you see?
Atoms of different elements have different atomic numbers. The atomic number tells us the number of protons (+ charge). If the atom is neutral, the number of electrons (-charge) equals the number of protons.
The mass number is the number of protons + the number of neutrons (0 charge). In the following, C-14, the 14 is the mass number. The atomic number for C can be found on the periodic table. C’s atomic number is 6, so it has 6 protons and 6 electrons. To find the neutrons, take the mass number minus the protons (14-6 = 8 neutrons).
In the Bohr Model, the protons and the neutrons are placed in the atomic nucleus while the electrons orbit around the nucleus in stationary levels. Each level can hold only a certain maximum number. The 1st up to 2 electrons, the 2nd up to 8 electrons, the 3rd up to 18 electrons, and the 4th up to 32 electrons.

38. Complete the table below using the information given for each atom
Complete the table below using the information given for each atom. Atom A has 3 protons and 4 neutrons. Atom B has 11 protons and 12 neutrons. Atom C has an atomic number of 19 and a mass number of 39. Atom D has an atomic number of 17 and a mass number of 35.
Atom
# of protons
# of neutrons
Atomic #
Mass #
# of electrons A B C D

39. Complete the table below using the information given for each atom
Complete the table below using the information given for each atom. Atom A has 3 protons and 4 neutrons. Atom B has 11 protons and 12 neutrons. Atom C has an atomic number of 19 and a mass number of 39. Atom D has an atomic number of 17 and a mass number of 35.
Atom
# of protons
# of neutrons
Atomic #
Mass #
# of electrons A 3 4 7 B 11 12 23 C 19 20 39 D 17 18 35

40. Let’s Draw some Bohr Models!

41. But…that can be a pain…
Most of the time we only really care about the valence electrons
Valence Electrons- electrons in the outermost shell
Also the GROUP NUMBER!!!

42. Valence Electrons are what react!

43. Lewis Dot Structures
Lewis dot diagrams- display the number of valence electrons (outermost electrons) around the element symbol
Used to show how atoms of different elements bond and form compounds
Hint- use group number to find valence electrons

44. Octet Rule-
Most atoms want to have 8 electrons in their outer shell

45. How to draw a Lewis Dot Structure
Find the group # (top of the row on the PT)
Write the symbol.
Draw dots around the symbol equal to the group number (if group 2- draw two dots)
Place dots one at a time around the top, right, bottom and left side of the atom before you double any up.

46. How to draw a Lewis Dot Structure
Find the group # (top of the row on the PT) Let’s do Phosphorus
Write the symbol. P
Draw dots around the symbol equal to the group number (if group 2- draw two dots)
Place dots one at a time around the top, right, bottom and left side of the atom before you double any up.

47. EXCEPTIONS!!! Helium- What is its group number?
Why doesn’t it make sense to draw that many dots?
Because it is easier for it to fill that first shell which only needs two electrons

48. Electron configurations (Bohr Models)

49. Lewis Dot Structures