Presentation is loading. Please wait.

Presentation is loading. Please wait.

Atoms, Molecules, and Ions

Published by하영 당 Modified over 5 years ago

Similar presentations

Presentation on theme: "Atoms, Molecules, and Ions"— Presentation transcript:

1 Atoms, Molecules, and Ions
Chapter 2 Atoms, Molecules, and Ions

2 Laws Conservation of Mass
Law of Definite Proportion – compounds have a constant composition by mass They react in specific ratios by mass Multiple Proportions – When two elements form more than one compound, the ratios of the masses of the second element that combine with one gram of the first can be reduced to small whole numbers

3 What?! Water has 8 g of oxygen per g of hydrogen
Hydrogen peroxide has 16 g of oxygen per g of hydrogen 16/8 = 2/1 Small whole number ratios

4 Example of Law Of Multiple Proportions
Mercury has two oxides. One is 96.2 % mercury by mass, the other is 92.6 % mercury by mass Show that these compounds follow the law of multiple proportion Speculate on the formula of the two oxides

5 Your Turn Nitrogen and oxygen form two compounds
Show that they follow the law of multiple proportions Amount N Amount O Compound A 1.206 g 2.755 g Compound B 1.651g 4.714 g

6 Dalton’s Atomic Theory
Elements are made up of atoms. Atoms of each element are identical. Atoms of different elements are different. Compounds are formed when atoms combine. Each compound has a specific number and kinds of atom. Chemical reactions are rearrangement of atoms. Atoms are not created or destroyed.

7 A Helpful Observation Gay-Lussac – under the same conditions of temperature and pressure, compounds always react in whole number ratios by volume Avagadro- interpreted that to mean at the same temperature and pressure, equal volumes of gas contain the same number of particles (called Avagadro’s hypothesis)

8 Experiments to determine what an atom was
J. J. Thomson- used Cathode ray tubes

9 Thomson’s Experiment Voltage source - +

10 Thomson’s Experiment Voltage source - +

11 Thomson’s Experiment Voltage source - +

12 - + Thomson’s Experiment Voltage source
Passing an electric current makes a beam appear to move from the negative to the positive end

13 - + Thomson’s Experiment Voltage source
Passing an electric current makes a beam appear to move from the negative to the positive end

14 - + Thomson’s Experiment Voltage source
Passing an electric current makes a beam appear to move from the negative to the positive end

15 - + Thomson’s Experiment Voltage source
Passing an electric current makes a beam appear to move from the negative to the positive end

16 Thomson’s Experiment Voltage source By adding an electric field

17 Thomson’s Experiment Voltage source + - By adding an electric field

18 Thomson’s Experiment Voltage source + - By adding an electric field

19 Thomson’s Experiment Voltage source + - By adding an electric field

20 Thomson’s Experiment Voltage source + - By adding an electric field

21 Thomson’s Experiment Voltage source + - By adding an electric field

22 Thomson’s Experiment Voltage source + -
By adding an electric field he found that the moving pieces were negative

23 Thomson’s Model Found the electron
Couldn’t find positive (for a while) Said the atom was like plum pudding A bunch of positive stuff, with the electrons able to be removed

24 Millikan’s Experiment
Atomizer - + Oil Microscope

25 Millikan’s Experiment
Atomizer Oil droplets - + Oil Microscope

26 Millikan’s Experiment
X-rays X-rays give some drops a charge by knocking off electrons

27 Millikan’s Experiment
+ 27

28 Millikan’s Experiment
- - + + They put an electric charge on the plates

29 Millikan’s Experiment
- - + + Some drops would hover

30 Millikan’s Experiment
- - - - - - - + + + + + + + +

31 Millikan’s Experiment
- - + + Measure the drop and find volume from 4/3πr3 Find mass from M = D x V

32 Millikan’s Experiment
- - + + From the mass of the drop and the charge on the plates, he calculated the charge on an electron

33 Radioactivity Discovered by accident Bequerel Three types
alpha – helium nucleus (+2 charge, large mass) beta – high speed electron gamma – high energy light (photon)

34 Rutherford’s Experiment
Used uranium to produce alpha particles Aimed alpha particles at gold foil by drilling hole in lead block Since the mass is evenly distributed in gold atoms alpha particles should go straight through Used gold foil because it could be made atoms thin

35 Florescent Screen Lead block Uranium Gold Foil

36 What he expected

37 Because

38 Because, he thought the mass was evenly distributed in the atom

39 What he got

40 How he explained it Atom is mostly empty Small, dense, positive piece at center Alpha particles are deflected by it if they get close enough +

41 +

42 Modern View The atom is mostly empty space Two regions
Nucleus – protons and neutrons Electron cloud – region where you have a chance of finding an electron

43 Sub-atomic Particles Z is atomic number = number of protons determines type of atom A is mass number = number of protons + neutrons Number of protons = number of electrons if neutral

44 Symbols A X Z 23 Na 11

45 Basic atomic structure
Activity on Basic atomic structure

46 Chemical Bonds The forces that hold atoms together
Covalent bonding – sharing electrons Makes molecules Chemical formula – the number and type of atoms in a molecule C2H6 – 2 carbon atoms, 6 hydrogen atoms Structural formula shows the connections, but not necessarily the shape

47 Structural Formula H H H C C H H H

48 There are also other model that attempt to show three dimensional shape
Ball and stick (like wooden models) Space Filling

49 Ions Atoms or groups of atoms with a charge
Cations – positive ions made by losing electron(s) Anions – negative ions made by gaining electron(s) Ionic bonding – held together by the opposite charges Ionic solids are called salts

50 Polyatomic Ions Sulfate, SO42-, nitrate, NO3-, hydroxide, OH-…
Groups of atoms that have a charge Yes, you have to memorize them (list on page 67)

51 Periodic Table

52 Metals Conductors Lose electrons Malleable and ductile

53 Nonmetals Brittle Gain electrons Covalent bonds

54 Semi-metals or Metalloids

55 Alkali Metals

56 Alkaline Earth Metals

57 Halogens

58 Transition metals

59 Noble Gases

60 Inner Transition Metals

61 +1 +2 -3 -2 -1

62 Naming compounds Two general types
Ionic – metal and non-metal or polyatomics (always start with metal) Covalent – nonmetals only (we will only learn the rules for covalent compounds with 2 elements)

63 Ionic compounds If the cation is monoatomic – write the name of the metal [include roman numeral if needed – but when is it needed?] If the cation is polyatomic (ammonium, NH4+) – write the name of it If the anion is monoatomic – write the name of it but change the ending to “-ide” (oxide) If the anion is polyatomic – just write the name of it

64 Ionic Formulas Charges must add up to zero
Get charges from table, name of metal ion, or memorized from the list Use parenthesis to indicate multiple polyatomics

65 Ionic Formulas sodium nitride sodium – Na is always +1
nitride – ide tells you it comes from the table (not a polyatomic) nitride is N-3

66 Na+1 N-3 Ionic Formulas sodium nitride Sodium – Na is always +1
Nitride – ide tells you it comes from the table nitride is N-3 doesn’t add up to zero Na+1 N-3

67 Na+1 N-3 Na3N Ionic Formulas Sodium nitride sodium- Na is always +1
nitride - ide tells you it comes from the table nitride is N-3 charges don’t add up to zero Need 3 Na+1 Na+1 N-3 Na3N

68 Covalent compounds Two words, with prefixes Prefixes tell you how many
mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca First element whole name with the appropriate prefix, except mono Second element, -ide ending with appropriate prefix

69 Acids Substances that produce H+ ions when dissolved in water
All acids begin with H Two types of acids Oxyacids Non-oxyacids

70 Naming acids If the formula has oxygen in it
write the name of the anion, but change ate to -ic acid ite to -ous acid Watch out for sulfuric and sulfurous H2CrO4 HMnO4 HNO2

71 Naming acids If the acid doesn’t have oxygen add the prefix hydro-
change the suffix -ide to -ic acid HCl H2S HCN

72 Formulas for acids Backwards from names
If it has hydro- in the name it has no oxygen anion ends in -ide No hydro, anion ends in -ate or -ite Write anion and add enough H to balance the charges

73 Practice Activity on Naming binary compounds
Activity on Naming ionic compounds with polyatomic ions and acids

74 Hydrates Some salts trap water crystals when they form crystals
these are hydrates. Both the name and the formula needs to indicate how many water molecules are trapped In the name we add the word hydrate with a prefix that tells us how many water molecules

75 Hydrates In the formula you put a dot and then write the number of molecules Calcium chloride dihydrate = CaCl2·2H2O Chromium (III) nitrate hexahydrate = Cr(NO3)3·6H2O

Download ppt "Atoms, Molecules, and Ions"

Similar presentations

Molecules, Ions and Their Compounds

Molecules, Ions and Their Compounds
The Early Models of the Atom

The Early Models of the Atom
Atoms, Molecules, and Ions

Atoms, Molecules, and Ions
CHAPTER 2 AP CHEMISTRY. LAWS LAW OF CONSERVATION OF MASS Mass cannot be created nor destroyed in a normal chemical reaction LAW OF DEFINITE PROPORTIONS.

CHAPTER 2 AP CHEMISTRY. LAWS LAW OF CONSERVATION OF MASS Mass cannot be created nor destroyed in a normal chemical reaction LAW OF DEFINITE PROPORTIONS.
Atoms, Molecules, and Ions

Atoms, Molecules, and Ions
History of the Atom.

History of the Atom.
Notes – Chapter Two Atoms, Molecules, and Ions. Section 2.2 Fundamental Chemical Laws  Law of conservation of Mass  Law of Definite Proportions  Law.

Notes – Chapter Two Atoms, Molecules, and Ions. Section 2.2 Fundamental Chemical Laws  Law of conservation of Mass  Law of Definite Proportions  Law.
Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 The Early History of Chemistry 4 Before 16th Century – Alchemy: Attempts (scientific.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 The Early History of Chemistry 4 Before 16th Century – Alchemy: Attempts (scientific.
Chapter 2 Atoms, Molecules, and Ions History of Atomic Theory Started with the Greeks and four elements (earth, air, water and fire) Democritus termed.

Chapter 2 Atoms, Molecules, and Ions History of Atomic Theory Started with the Greeks and four elements (earth, air, water and fire) Democritus termed.
Chapter 2 Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements. n Alchemy n 1660 - Robert Boyle- experimental.

Chapter 2 Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements. n Alchemy n Robert Boyle- experimental.
Symbols X A Z Na 23 11. Chemical Bonds n The forces that hold atoms together. n Covalent bonding - sharing electrons. n Makes molecules. n Chemical formula-

Symbols X A Z Na Chemical Bonds n The forces that hold atoms together. n Covalent bonding - sharing electrons. n Makes molecules. n Chemical formula-
Atoms, Molecules, and Ions Chapter II A Quick Survey.

Atoms, Molecules, and Ions Chapter II A Quick Survey.
1 Chapter 5 Atoms, Molecules, and Ions 2 History n Greeks n Democritus and Leucippus - atomos n Aristotle- 4 elements. n Alchemy-experimentation n 1660.

1 Chapter 5 Atoms, Molecules, and Ions 2 History n Greeks n Democritus and Leucippus - atomos n Aristotle- 4 elements. n Alchemy-experimentation n 1660.
Chapter 2 Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements. n Alchemy n 1660 - Robert Boyle- experimental.

Chapter 2 Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements. n Alchemy n Robert Boyle- experimental.
Atomic Structure Atoms and their structure Mr. Bruder.

Atomic Structure Atoms and their structure Mr. Bruder.
Unit # 4 Atomic Theory History Greeks n Democritus (460-370BC) – Matter is made of atoms. - Different kinds of shapes and sizes n Aristotle ( 364 -322.

Unit # 4 Atomic Theory History Greeks n Democritus ( BC) – Matter is made of atoms. - Different kinds of shapes and sizes n Aristotle (
A.P. Ch. 2 Review Work Atoms, Molecules, Ions. Conservation of mass: during a reaction the amount of material you start with equals the amount you end.

A.P. Ch. 2 Review Work Atoms, Molecules, Ions. Conservation of mass: during a reaction the amount of material you start with equals the amount you end.
Chapter 2 (Part I) Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements n Alchemy n 1660 - Robert Boyle-

Chapter 2 (Part I) Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements n Alchemy n Robert Boyle-
Chapter 2 Atoms, Molecules, and Ions History n Greek philosophers n Democritus and Leucippus - atomos n Aristotle- 4 elements: Earth, Air, Fire, and.

Chapter 2 Atoms, Molecules, and Ions History n Greek philosophers n Democritus and Leucippus - atomos n Aristotle- 4 elements: Earth, Air, Fire, and.
The Atom Philosophy to Scientific Theory I. The Atom: Philosophy to Scientific Theory  Ancient Greek Philosophers theorized on what the universe was.

The Atom Philosophy to Scientific Theory I. The Atom: Philosophy to Scientific Theory  Ancient Greek Philosophers theorized on what the universe was.

Similar presentations

Ads by Google