1. ___Unsaturated sugar water ___Ketchup ___Insoluble PbI2 in water
Identify each as HOMOgeneous (HO) or HETEROgeneous (HE);
___Unsaturated sugar water
___Ketchup
___Insoluble PbI2 in water
___Brass
___Chunky llama snot HO ? HO HE HO HE

2. Chapter 2 Atoms, Molecules, and Ions
John D. Bookstaver
St. Charles Community College
St. Peters, MO
 2006, Prentice Hall, Inc.
“Tweaked”
by Robert Hernandez
Seabreeze Highschool
2015

3. Atomic Theory of Matter
Originally proposed by Democritus…
But ignored for 2,500 years…
Because Aristotle had a DIFFERENT idea…
Earth, Wind, Fire, Water…
Alexander was Aristotle’s student…
Alexander was kind of a big deal.
John Dalton ( ) atoms are smallest, same are identical and diff are diff, not created or destroyed in chem rxns (how are they created?), compounds can form from elements and have same #s and kind of elements (Law of…) 3

4. Atomic Theory of Matter
atoms are the fundamental building blocks of matter reemerged in the early 19th century, championed by John Dalton.
Dalton’s Atomic Theory
-smallest
-same atoms are identical
-not changed in chem rxns
-consistent compounds form
John Dalton ( ) atoms are smallest, same are identical and diff are diff, not created or destroyed in chem rxns (how are they created?), compounds can form from elements and have same #s and kind of elements (Law of…)
Democritus
was right!

5. Law of Constant Composition
Also known as the law of definite proportions.
The elemental composition of a pure substance never varies.
2 H’s and 1 O is ALWAYS water.
Water is ALWAYS 2 H’s and 1 O.

6. Law of Conservation of Mass
The total mass of substances present after a chemical process is the same as the mass of substances present before the process took place. 2 2
___H2 + ___O ___H2O 1 1 1 1 1 16
Why we balance equations. 1 16 16 16 1 1 =

7. The Atom, circa 1900: “plums” “Plum pudding” model, by JJ Thomson.
Do This…
On your notes, draw in the “plums”.
The Atom, circa 1900:
“plums”
“Plum pudding” model, by JJ Thomson.
Positive sphere of matter (pudding) with negative electrons (plums) imbedded in it.
“puddin’”

8. The Electron
Streams of negatively charged particles were found to emanate from cathode tubes.

9. Discovery of the Electron
How Thomson did it…
Dx- = e- / m-
+++
Dx- H2
Dx+
- - -
Dx+ = e+ / m+ m-
Dx- = ___
Dx+
|e+| = |e-|
mH+ m+

10. Radioactivity + - +++ - - -
Using a similar setup, replacing the hydrogen with a radioactive emitter…
+++ H2
- - -
Ernest Rutherford discovered three types of radiation:
Charge…
Alpha  particles
Beta  particles
Gamma  rays + -

11. Discovery of the Nucleus
Ernest Rutherford shot  particles at a thin sheet of gold foil and observed the pattern of scatter of the particles. Discuss.

12. Rutherford’s Gold Foil Experiment?
Rutherford’s Gold Foil Experiment
RaBr2 +
Rutherford took a chunk of lead...
A decent radiation insulator
He borrowed radium bromide…
From his friend Marie Curie…
RaBr2 emits a particles…
Positively charged Helium nuclei (He+2)
Which can be detected by a device his friend Hans Geiger invented.
Rutherford detected ~132,000 hits per minute.
132000

13. Rutherford’s Gold Foil Experiment
132000
Rutherford then inserted a VERY THIN piece of gold foil along the a particles’ path…
Only 1 x 10-6 meters… 1 micron (1m)
human hair diameter = 100m
Rutherford detected ~132,000 hits per minute.
No change… As if the Gold wasn’t there…

14. Rutherford’s Gold Foil Experiment20
132000
But when the detector was slid…
.. ricochets were detected…
Not a lot, ~20 hits per minute.
The Gold was there after all.

15. Rutherford’s Gold Foil Experiment
132000 20
Proportion of impacts = = 2 x 10-4
132,000

16. The Nuclear Atom 1x 10-4 Ao Nucleus = 1 x 10-14m
Atom Diameter = 1 x 10-10m
1 Ao
Must have deflected off large massive particles,
Since some particles were deflected at large angles, Thompson’s model could not be correct.

17. Rutherford’s Gold Foil Experiment
Actually performed with X-Ray paper
Repeated with Platinum, Silver, etc…

18. Try it out!
Figure out the shape of the target using the deflections of the beams… 2 1 2 3 1 1 1 2 2 3 3 4 4 5 5 4 3 4

19. Rutherford’s Findings
Most of the particles passed right through
A few particles were deflected
VERY FEW were greatly deflected
“Like howitzer shells bouncing off of tissue paper!”
Conclusions:
The nucleus is small
The nucleus is dense
The nucleus is positively charged

20. Mass Spectrometry atomized, ionized element sample magnetic field
Signal
Intensity
Using colored pencils, fill in the diagram and graph on your notes.
Atomic Mass

21. isotopes separated by difference in mass
Mass Spectrometry
atomized,
ionized
magnetic field
element sample
isotopes separated by difference in mass
~75%
~25%
WS 2a
(35)(~0.75) + (37)(~0.25) = ?

22. Elements are symbolized by one or two letters.
Symbols of Elements
Mass Number the total number of PROTONS and NEUTRONS in the atom. 12 C 6
Atomic Number (Z) Number of PROTONS in an element.
All atoms of the same element have the same number of PROTONS.
Elements are symbolized by one or two letters.

23. Isotopes:
Atoms of the same element with different masses.
Isotopes have different numbers of neutrons. 11 6 C 12 6 C 13 6 C 14 6 C
What are 3 isotopes of H (protium, deuterium, tritium) draw on board, deut and trit for fusion

24. Isotopes:
Isotopes are atoms of the same element having different masses due to varying numbers of neutrons.
Isotope
Protons
Electrons
Neutrons
Nucleus
Hydrogen–1
(protium) 1
Hydrogen-2
(deuterium)
Hydrogen-3
(tritium) 2

25. Average Mass Avg. Mass = (Mass1)(%) + (Mass2)(%) …
Average mass is calculated from the isotopes of an element weighted by their relative abundances.
chlorine-35 (34.97), which has a natural abundance of 75.53%, and
chlorine-37 (36.96), which has a natural abundance of 24.47%.
Show example of weighted average at mass 75% + 25%) = 35.5
(34.97)(0.7553) + (36.96)(0.2447) = 35.45
Avg. Mass = (Mass1)(%) + (Mass2)(%) …

26. 1H 2H 3H Hydrogen = 1.0078 1.01 Hydrogen = + + Hydrogen = 1.0078
Atomic mass is the average of all the naturally isotopes of that element.
Sig-Figs
Hydrogen =
1.01
Isotope
Symbol
nucleus
% in nature
Hydrogen-1 1H
1 proton
0 neutrons
99.985%
Hydrogen-2 2H
1 protons
1 neutrons
0.15%
Hydrogen-3 3H
2 neutrons
<0.00%
Hydrogen =
1(0.999)
2(0.0015)
3(0.00)
Hydrogen =

27. Carbon = 12.013 12.01 Carbon = + + 14(0.0001) Carbon = 12.012
What is the atomic mass of Carbon?
Sig-Figs
Carbon =
12.01
Isotope
Symbol
nucleus
% in nature
Carbon-12
12C
6 protons
6 neutrons
98.89%
Carbon-13
13C
7 neutrons
1.11%
Carbon-14
14C
8 neutrons
<0.01%
Carbon =
14(0.0001)
12(0.9889)
13(0.0111)
Carbon = 27

28. Atomic Number Element # of protons Atomic # (Z) Carbon 6 Phosphorus 15
Atomic number (Z) of an element is the number of protons in the nucleus of each atom of that element.
Element
# of protons
Atomic # (Z)
Carbon 6
Phosphorus 15
Gold 79 = = =

29. Mass Number Nuclide p+ n0 e- Mass #
Mass number is the number of protons and neutrons in the nucleus of an isotope.
Mass # = p+ + n0
Nuclide p+ n0 e-
Mass #
Oxygen - 10 - 33 42
- 31 15 18 8 8 18
Arsenic 75 33 75
Phosphorus 16 15 31
Complete the table using the periodic table… and your BRAIN!

30. Periodic Table:
How are the elements arranged? Used to be by at. mass and repeated properties were seen, now better by at. #.

31. Periodicity
Reactivities are based on valence electrons!
chemical properties of elements, display a repeating pattern of reactivities.

32. Periodic Table The rows on the periodic chart are periods.
Columns are groups.
Elements in the same group have similar chemical properties.
Why do they have similar props? (same val #) (electrons are the deciding factor of reactivity)

33. Groups
These FOUR groups are known by their names.

34. Periodic Table Metals are on the left side. Nonmetals are on
the right side. H
(except H). Al Po
Metalloids border the stair-step
EXCEPT Al and Po

35. Molecular Compounds
Molecular compounds almost always contain only nonmetals.
Molecular compounds form COVALANT bonds.

36. Diatomic Molecules “H-air-ogens” H N O F Cl 2 2 2 2 2 2 2 Br I
Seems like all gases, why not noble gases? (have octet already)
These seven elements occur naturally as molecules containing two atoms.

37. Types of Formulas
Empirical formulas give the lowest whole-number ratio of atoms of each element in a compound. Molecular formulas give the exact number of atoms of each element in a compound. emp. CH3 mol. C2H6
More on these in Chp 3

38. Naming Molecular Compounds
Prefix Meaning
Mono 1 Di
Tri 3 4
Penta 5
Hexa 6
Hepta
Octo 8 9
Deca 10 2
Tetra 7
Nona

39. Naming Molecular Compounds
diphosphorus pentoxide
CCl4
- carbon tetrachloride CO
- carbon monoxide
N2O -
dinitrogen monoxide

40. Ions When atoms lose or gain electrons, they become ions.
Cations are positive and are formed by elements on the left side of the periodic chart.
Anions are negative and are formed by elements on the right side of the periodic chart.

41. Ionic Bonds
Ionic compounds (such as NaCl) are generally formed between metals and nonmetals.

42. Writing Ionic Formulas-3
Mg N  Mg N +2 3 2
Because compounds are electrically neutral, one can determine the formula this way:
The charge on the cation becomes the subscript on the anion.
The charge on the anion becomes the subscript on the cation.
If these subscripts are not in the lowest whole-number ratio, divide them by the Greatest Common Factor .
Do Al and SO4 on board

43. Common Cations
Group 1, 2, 3 charges

44. Common Anions
Group 7, 6, 5 charges

45. Polyatomic Ions YOU MUST KNOW…
Ammonium NH4 +
nitrite NO2 - 1
nitrate NO3 - 1
sulfate SO4 - 2
sulfite SO3 – 2
ThioSulfate S2O3-2
Thiocyanate SCN-
carbonate CO3 - 2
acetate C2H3O2 - 1
citrate C6H5O7-3
cyanide CN -  
borate BO3 -3
orthosilicate SiO4 -4
peroxide O2 - 2
hydroxide OH -
hypochlorite ClO - 1
chlorite ClO2 - 1
chlorate ClO3 - 1
perchlorate ClO4 - 1
phosphate PO4 - 3
pyrophosphate P2O7 -4

46. Patterns in Oxyanion Nomenclature
When there are two oxyanions involving the same element:
The one with fewer oxygens ends in -ite
NO2− nitrite SO32− sulfite
The one with more oxygens ends in -ate
NO3− nitrate SO42− sulfate

47. Patterns in Oxyanion Nomenclature
The one with the fewest oxygens has the prefix hypo- and ends in -ite
ClO− hypochlorite
The one with the most oxygens has the prefix per- and ends in -ate
ClO4− perchlorate

48. Patterns in Oxyanion Nomenclature
Name Number of oxygen atoms
per(element)ate
(element)ate
(element)ite
hypo(element)ite
If only two members, the endings are
–ite and –ate.
More O’s

49. Ionic Nomenclature Write the name of the cation.
If anion is an element, change ending to –ide or write the name of the polyatomic ion.
If the cation can have multiple charges, write the charge as a Roman numeral in parentheses.
Iron (II) chloride,
FeCl3
“Naming”
FeCl2
Iron (III) chloride

50. Writing Ionic Compound Formulas
Example: Barium nitrate
1. Write the formulas for the cation and anion, including CHARGES!
Ba+2
( )
NO3-
2. Check to see if charges are balanced. 2
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
Not balanced!

51. Writing Ionic Compound Formulas
Example: Ammonium sulfate
1. Write the formulas for the cation and anion, including CHARGES!
( )
NH4+
SO4-2
2. Check to see if charges are balanced. 2
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
Not balanced!

52. Writing Ionic Compound Formulas
Example: Iron(III) chloride
1. Write the formulas for the cation and anion, including CHARGES!
Fe3+
Cl-
2. Check to see if charges are balanced. 3
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
Not balanced!

53. Writing Ionic Compound Formulas
Example: Aluminum sulfide
1. Write the formulas for the cation and anion, including CHARGES!
Al3+
S2-
2. Check to see if charges are balanced. 2 3
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
Not balanced!

54. Writing Ionic Compound Formulas
Mg2+
CO32-
Example: Magnesium carbonate
1. Write the formulas for the cation and anion, including CHARGES!
They are balanced!
2. Check to see if charges are balanced.

55. Writing Ionic Compound Formulas
Example: Zinc hydroxide
NOTE: Zinc is ALWAYS +2
1. Write the formulas for the cation and anion, including CHARGES!
( )
Zn2+
OH- 2
2. Check to see if charges are balanced.
Not balanced!
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.

56. Writing Ionic Compound Formulas
Example: Aluminum phosphate
1. Write the formulas for the cation and anion, including CHARGES!
Al3+
PO43-
2. Check to see if charges are balanced.
They ARE balanced!

57. Naming Ionic Compounds
CaCl2
1. Cation first, then anion
2. cation = name of the element
Ca2+ = calcium ion
3. anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride

58. Naming Ionic Compounds
PbCl2
Metals with multiple oxidation states
some metal forms more than one cation use Roman numeral in name, PbCl2 Pb2+ is the lead (II) cation PbCl2 = lead (II) chloride

59. Which Big Ideas did this chapter address?
Structure of Matter:
The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangements of atoms. These atoms retain their identity in chemical reactions
2. Properties of Matter:
Chemical and physical properties of materials can be explained by the structure and the arrangement of atoms, ions, or molecules and the forces between them.
3. Chemical Reactions: Changes in matter involve the rearrangement and/or reorganization of atoms and/or the transfer of electrons
4. Rates of Chemical Reactions:
Rates of chemical reactions are determined by details of the molecular collisions.
5. Thermodynamics:
The laws of thermodynamics describe the essential role of energy and explain and predict the direction of changes in matter
6. Equilibrium:
Any bond or intermolecular attraction that can be formed can be broken. These two processes are in a dynamic competition, sensitive to initial conditions and external perturbations.

60. Learning Objectives NO2
1 (of 3)
1.02 The student is able to select and apply mathematical routines to mass data to identify or infer the composition of pure substances and/or mixtures? O N
What is the EMPIRICAL formula of this molecule?
Dinitrogen tetroxide is used as a rocket fuel in the titan rockets. What is the ratio of oxygen to nitrogen in the fuel tanks?
2:1
NO2

61. Learning Objectives
2 (of 3)
1.03 Can you select and apply mathematical relationships to mass data in order to justify a claim regarding the identity and/or estimated purity of a substance?
Sugar water
Total
cylinder -50.0
404.5
What is the temperature of this saturated sugar solution?
(g.cylinder mass = 50.0g)
Sugar
Sugar water water
sugar = 304.5
454.5g
~62oC

62. Learning Objectives
3 (of 3)
1.14 The student is able to use data from mass spectrometry to identify the elements and the masses of individual atoms of a specific element.
What is the [ ] of a solution with an absorption of 1.7 in the 230nm wavelength?
~ M