Chapter 2 Atoms Molecules and Ions AP Chemistry
- Slides: 80
Chapter 2 Atoms, Molecules, and Ions AP Chemistry West Valley High School Mr. Mata
History Greeks n Democritus and Leucippus – “atomos” n Aristotle- elements (earth, water, fire, air) n Alchemy (tried to convert Pb Au) n 1660 - Robert Boyle- experimental definition of element. n Lavoisier- Father of modern chemistry n He wrote the book- used measurement n
Laws Conservation of Mass n Law of Definite Proportion- compounds have a constant composition by mass. n They react in specific ratios by mass. n Multiple Proportions- When two elements form more than one compound, the ratios of the masses can be reduced to small whole numbers. n
What? ! Water (H 2 O) has 16 g of O per 2 g of H or 8 g O per 1 g of H. n Hydrogen peroxide (H 2 O 2) has 32 g of O per 2 g of H or 16 g of O per 1 g of H. n If both H 2 O and H 2 O 2 form from reactants, they would have a 16 g/8 g ratio = 2/1 or a 2: 1 ratio. n Small whole number ratios. n
Dalton’s Atomic Theory 1. Elements are made up of atoms n 2. Atoms of each element are identical; atoms of different elements are different. n 3. Compounds are formed when atoms combine. Each compound has a specific number and kinds of atom. n 4. Chemical reactions are rearrangements of atoms. Atoms are not created nor destroyed. n
A Helpful Observation Gay-Lussac- under the same conditions of temperature and pressure, compounds always react in whole number ratios by volume. n Avogadro- interpreted that to mean: at the same temperature and pressure, equal volumes of gas contain the same number of particles n (called Avogadro’s hypothesis) n
Experiments to determine what an atom was n J. J. Thomson- used Cathode ray tubes
Thomson’s Experiment - Voltage source +
Thomson’s Experiment - Voltage source +
Thomson’s Experiment - Voltage source +
Thomson’s Experiment n Voltage source + Passing an electric current makes a beam appear to move from the negative to the positive end
Thomson’s Experiment n Voltage source + Passing an electric current makes a beam appear to move from the negative to the positive end
Thomson’s Experiment n Voltage source + Passing an electric current makes a beam appear to move from the negative to the positive end
Thomson’s Experiment n Voltage source + Passing an electric current makes a beam appear to move from the negative to the positive end
Thomson’s Experiment Voltage source n By adding an electric field
Thomson’s Experiment Voltage source + n By adding an electric field
Thomson’s Experiment Voltage source + n By adding an electric field
Thomson’s Experiment Voltage source + n By adding an electric field
Thomson’s Experiment Voltage source + n By adding an electric field
Thomson’s Experiment Voltage source + n By adding an electric field
Thomson’s Experiment Voltage source + n By adding an electric field he found that the moving pieces were negative
Thomsom’s Model Found the electron. n Couldn’t find positive (for a while) n Said the atom was like plum pudding. n A bunch of positive stuff, with the electrons able to be removed. n
Millikan’s Experiment Atomizer + Oil Microscope
Millikan’s Experiment Atomizer Oil droplets + Oil Microscope
Millikan’s Experiment X-rays give some drops a charge by knocking off electrons
Millikan’s Experiment +
Millikan’s Experiment - - + + They put an electric charge on the plates
Millikan’s Experiment - - + + Some drops would hover
Millikan’s Experiment - - - - + + + +
Millikan’s Experiment - - + + Measure the drop and find volume from 4/3πr 3 Find mass from M = D x V
Millikan’s Experiment - - + + From the mass of the drop and the charge on the plates, he calculated the charge on an electron
Radioactivity Discovered by accident n Henri Bequerel n Three types – alpha- helium nucleus (+2 charge, large mass) – beta- high speed electron – gamma- high energy light n
Rutherford’s Experiment Used uranium to produce alpha particles. n Aimed alpha particles at gold foil by drilling hole in lead block. n Since the mass is evenly distributed in gold atoms alpha particles should go straight through. n Used gold foil because it could be made atoms thin. n
Lead block Uranium Florescent Screen Gold Foil
What he expected
Because
Because, he thought the mass was evenly distributed in the atom
What he got
How he explained it Atom is mostly empty n Small dense, positive piece center n Alpha particles are deflected by it if they get close enough n at +
Modern View The atom is mostly empty space. n Two regions. n Nucleus- protons and neutrons. n Electron cloud- region where you have a chance of finding an electron. n
Sub-atomic Particles Z - atomic number = number of protons determines type of atom n A – atomic mass = number of protons + neutrons n Number of protons = number of electrons if neutral n
Symbols A X Z 23 Na 11
Chemical Bonds The forces that hold atoms together. n Covalent bonding - sharing electrons. n makes molecules. n Chemical formula- the number and type of atoms in a molecule. n C 2 H 6 - 2 carbon atoms, 6 hydrogen atoms, n n Structural formula shows the connections, but not necessarily the shape.
n Structural Formula H H C H H
There also other model that attempt to show three dimensional shape n Ball and stick (see the models in room) n n Space Filling
Ions Atoms or groups of atoms with a charge. n Cations- positive ions - get by losing electrons(s). n Anions- negative ions - get by gaining electron(s). n Ionic bonding- held together by the opposite charges. n Ionic solids are called salts. n
Polyatomic Ions Groups of atoms that have a charge. n Yes, you have to memorize them. n List on page 65 of Zumdahl (9 th edition). n
Periodic Table
Metals Conductors n Lose electrons n Malleable and ductile n
Nonmetals Brittle n Gain electrons n Covalent bonds n
Semi-metals or Metalloids
Alkali Metals
Alkaline Earth Metals
Halogens
Transition metals
Noble Gases
Inner Transition Metals
+1+2 -3 -2 -1
Naming compounds Two types. n Ionic - metal and non metal or polyatomics. n Covalent- we will just learn the rules for 2 non-metals. n
Ionic compounds If the cation is monoatomic- Name the metal (cation) just write the name. n If the cation is polyatomic- name it n If the anion is monoatomic- name it but change the ending to -ide n If the anion is poly atomic- just name it. n practice n
Covalent compounds Two words, with prefixes. n Prefixes tell you how many. n mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca (know these first ten prefixes). n First element whole name with the appropriate prefix, except mono. n Second element, -ide ending with appropriate prefix. n Practice n
Ionic Compounds Have to know what ions they form n off table, polyatomic, or figure it out n Ca. S calcium sulfide n K 2 S potassium sulfide n n Al. PO 4 K 2 SO 4 n Fe. S n Co. I 3 n aluminum phosphate potassium sulfate iron sulfide cobalt iodide
Ionic Compounds n Fe 2(C 2 O 4) iron oxalate n Mg. O magnesium oxide n Mn. O manganese oxide n KMn. O 4 potassium permanganate n NH 4 NO 3 ammonium nitrate n Hg 2 Cl 2 mercury chloride n Cr 2 O 3 chromium oxide
Ionic Compounds KCl. O 4 n Na. Cl. O 3 n YBr. O 2 n Cr. Cl. O 2 n potassium perchlorate sodium chlorate yttrium bromite chromium chlorite
Naming Covalent Compounds CO 2 n CO n CCl 4 n N 2 O 4 n Xe. F 6 n N 4 O 4 n P 2 O 10 n carbon dioxide carbon monoxide carbon tetrachloride dinitrogen tetraoxide xenon hexafloride tetranitrogen tetraoxide diphosphorous decaoxide
Writing Formulas Two sets of rules, ionic and covalent. n To decide which to use, decide what the first word is. n If is a metal or polyatomic use ionic. n If it is a non-metal use covalent. n
Ionic Formulas Charges must add up to zero. n get charges from table, name of metal ion, or memorized from the list. n use parenthesis to indicate multiple polyatomics. n
Ionic Formulas Sodium nitride n sodium- Na is always +1 n nitride - ide tells you it comes from the table n nitride is N-3 n
Ionic Formulas Sodium nitride n sodium- Na is always +1 n nitride - ide tells you it comes from the table n nitride is N-3 n doesn’t add up to zero n +1 Na -3 N
Ionic Formulas Sodium nitride n sodium- Na is always +1 n nitride - ide tells you it comes from the table n nitride is N-3 n doesn’t add up to zero n Need 3 Na n +1 Na -3 N Na 3 N
Ionic Compounds Sodium sulfite n calcium iodide n Lead (II) oxide n Lead (IV) oxide n Mercury (I) sulfide n Barium chromate n Na 2 SO 3 Ca. I 2 Pb. O 2 Hg 2 S Ba. Cr. O 4
Covalent compounds The name tells you how to write the formula n Sulfur dioxide SO 2 n diflourine monoxide F 2 O n nitrogen trichloride NCl 3 n diphosphorus pentoxide P 2 O 5 n
More Names and formulas
Acids Substances that produce H+ ions when dissolved in water n All acids begin with H n Two types of acids n Oxyacids n non oxyacids n
Naming acids If the formula has oxygen in it n write the name of the anion, but change – ate to -ic acid – ite to -ous acid n Watch out for sulfuric and sulfurous n HCl. O 4 perchloric acid n H 2 SO 3 sulfurous acid n HNO 2 nitrous acid n
Naming acids If the acid doesn’t have oxygen n add the prefix hydron change the suffix -ide to -ic acid n HCl hydrochloric acid n H 2 S hydrosulfuric acid n HCN hydrocyanic acid n
Formulas for acids Backwards from names n If it has hydro- in the name; no oxygen. n anion ends in –ide. n No hydro, anion ends in -ate or –ite. n Write anion and add enough H to balance the charges. n
Hydrates Some salts trap water crystals when they form crystals. n these are hydrates. n Both the name and the formula needs to indicate how many water molecules are trapped. n In the name we add the word hydrate with a prefix that tells us how many water molecules. n
Hydrates In the formula you put a dot and then write the number of molecules. n Calcium chloride dihydrate = Ca. Cl 2· 2 H 2 O n Chromium (III) nitrate hexahydrate = Cr(NO 3)3· 6 H 2 O n
- Chapter 2 atoms molecules and ions
- Atoms molecules and ions
- Atoms molecules and ions
- Atoms molecules and ions
- Atoms molecules and ions
- Atoms ions and molecules
- Atoms ions and molecules
- Collision theory states that
- Positive ions and negative ions table
- Relationship between atoms and molecules
- Atoms elements molecules and compounds worksheet
- 3bacl2 counting atoms
- Interacting molecules or ions
- Organic molecules vs inorganic molecules
- How does a positive ion form
- Atoms or ions are considered isoelectronic if
- Why do atoms combine to form molecules
- Periodic table of elements regents
- What is a polyatomic ion definition
- Spectator ions equation example
- Chemsheets as 1017 shapes of molecules
- Chemistry molecules
- Different molecular structures
- Shapes of molecules a level chemistry
- Chemsheets shapes of molecules answers
- Ap chemistry electronic structure of atoms
- Chapter 6 section 1 atoms elements and compounds
- Chapter 6 section 1 atoms elements and compounds
- Chapter 13 review ions in aqueous solutions
- Ions charged particles in solution
- Ib organic chemistry functional groups
- Inorganic vs organic chemistry
- Chapter 3 molecules of life
- Chapter 4 section 2 the structure of atoms
- Chapter 4 arrangement of electrons in atoms
- Stable electron configurations are likely to contain
- Chapter 6 electronic structure of atoms answers
- Chapter 5 review arrangement of electrons in atoms
- Electronic structure of atoms
- Chapter 3 atoms the building blocks of matter
- Which subatomic particle has the least mass
- Monatomic and polyatomic ions
- Charge of ammonium
- Polyatomic compounds
- Auric nitride
- Electrostatic attraction between positive and negative ions
- Srim the stopping and range of ions in matter
- Polyatomic ions grade 10
- Freezing point chapter 13
- Name and symbols of some ions
- Ions and ionic bonding cornell doodle notes
- Classify the following unbalanced chemical equations
- Molecules of solid liquid and gas
- Chiral or achiral
- Polar and nonpolar similarities
- The molecules used to cut copy and connect the dna
- Molecular shape and polarity
- Non polar molecules that include fats oils and cholesterol
- Bead like structures formed by dna and histone molecules
- Electrons in atoms section 1 light and quantized energy
- How many atoms
- Electrons in atoms section 1 light and quantized energy
- Properties of atoms and the periodic table
- The lowest allowable energy state of an atom is called
- Center for bits and atoms
- Electrons in atoms section 2 quantum theory and the atom
- Counting atoms and balancing equations
- Chemistry in biology section 2 chemical reactions
- Atoms and radioactivity
- Counting atoms and balancing equations worksheet
- Isotopes pogil
- Quantum theory and the electronic structure of atoms
- Chemistry matter and change chapter 7
- Chapter 10 study guide the mole
- Chemical equations and reactions chapter 8 review
- Chemistry chapter 9 chemical names and formulas
- 1s 22 s22 p63 s23 p64 s2
- Chemistry matter and change chapter 6
- Chapter 10 study guide the mole
- Chemistry matter and change answer key chapter 2
- Oxygen periodic trends