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45 Cards in this Set
- Front
- Back
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JJ Thompson`s Experiments - studied ________ using a _________ -_______ is evacuated from the tube - ______ ________ ________ are connected to ____________ - the ___________________ emits a __________ - Use a ______________ to see the ______________ |
1) radiation using a cathode ray tube 2) Air is evacuated from the tube 3) Two metal plates are connected to a high voltage source 4) the negative charge plate (cathode) emits a mysterious invisible ray 5) Use a fluorescent coating (zinc sulfide) to see the ray and deflect with a magnet
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JJ Thompson`s Experiments cont`d - two electrically charged plates and a ________ were added to the __________ of the _____________ - with __________________________, cathode ray strikes point A -with ___________________________, cathode ray strikes point C -With ___________________, cathode ray strikes point B |
1) two electrically charged plates and a magnet were added to the outside of the cathode ray tube 2) with magnetic field on and electric field off, cathode ray strikes point A 3) with magnetic field off and electric field on, cathode ray strikes point C 4) With both fields off or fields balancing each other, cathode ray strikes point B |
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JJ Thompson`s hypothesis |
- He proposed that the mysterious cathode rays were streams of particles much smaller than atoms -attracted to the positively charged plate -repelled by the negatively charged plate -particles are therefore negatively charged electrons -measured ratio of charge to mass (e/m)
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Thompson`s next hypothesis |
- Atoms contain electrons -atoms are electrically neutral -an atom must contain an equal number of positive and negative charges - plum pudding model ( atom is envisioned as electrons surrounded by a soup of positive charge, like raisins surrounded by pudding) - this plum pudding model was disproved by an experiment done by Ernest Rutherford when he discovered the nucleus of an atom |
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Rutherford`s Experiment |
- probed the structure of atoms with alpha particle (+) from a radioactive source - used very thin foils of gold and other metals as targets for the alpha particles - most of the particles penetrated the foil with little or no deflection - an occasional particle bounced back from where it had come from |
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Rutherford`s hypothesis |
- If Thompson`s model was correct, the spread out positive charge would not deflect any of the alpha particles - Most of the atom must be empty space - The atoms positive charge must be concentrated in the nucleus, a dense core within the atom - the positive charged particles in the nucleus are protons
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James Chadwick`s experiments |
- Chadwick bombarded a thin sheet of beryllium with alpha particles - very high energy radiation was emitted - the emitted rays were electrically neutral with mass slightly greater than that of protons - the neutral particles in nucleus are neutrons - over 99.9% of the volume of an atom is empty space
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Subatomic particles charge and mass of electron, proton and neutron |
Electrons: -1 ; 9.10939 x 10^-28 g Protons: +1 ; 1.67262 x 10^-24 g Electrons: 0 ; 1.67493 x 10^-24 g
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Atomic Number and Mass Number - what is atomic mass measured in? |
Atomic number equals the number of protons and the number of electrons Mass number equals the number of protons plus the number of neutrons - atomic mass is measured in atomic mass unit (amu) |
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Why are the atomic mass units not exact whole numbers for all of the elements? |
The existence of isotopes - isotopes of an atom have the same number of protons but different number of neutrons -atomic mass is the average mass of the naturally occurring isotopes |
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Deuterium and Tritium |
Deuterium- also called "heavy hydrogen", used in nuclear fission reactions, used as a non-radioactive tracer to study metabolic pathways
Tritium- radioactive isotope used in nuclear weapons
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Element and latin name |
Sodium - Natrium Potassium- kalium iron - Ferrum Copper- cuprum silver- argentum tin- stannum antimony- stibnium gold- aurum mercury - hydragyrum lead- plumbum
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Properties of subatomic particles (charge and mass) |
Electron -1 ; .0005486 amu = 0 amu Proton +1 ; 1.007277 amu = 1 amu Neutron 0 ; 1.008665 amu = 1 amu |
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Electrons - Electrons are not _________________ - They are in ________ around the __________ - _________ closest to the nucleus has the ______________ -________ furthest from the nucleus has the ______________ |
1) Electrons are not arranged randomly 2) They are in layers around the nucleus (shells or energy levels) 3) Shells closest to the nucleus has the lowest energy 4) Shells furthest from the nucleus has the highest energy |
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Electron Shells 1st shell can hold up to ______ 2nd shell can hold up to ________ 3rd shell can hold up to _________ 4th shell can hold up to __________ Outermost shell is the ____________ The valence shell contains ___________________ All electrons in inner shells are ________________ Elements whose shells are not filled are what? |
1st shell can hold up to 2 electrons 2nd shell can hold up to 8 electrons 3rd shell can hold up to 18 electrons 4th shell can hold up to 32 electrons Outermost shell is the valence shell The valence shell contains valence electrons All electrons in inner shells are core electrons Elements whose shells are not filled are chemically reactive |
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Electron Transition - Electrons can move ___________ - When an electron gains energy it does what ? - When an electron loses energy it does what? |
1) Electrons can move between shells 2) When an electron gains energy it moves from an inner shell to an outer shell 3) When an electron loses energy it moves from an outer shell to an inner shell, light of specific energy and wavelength is emitted |
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Periodic Table - The elements in each row (______) have a ____________ in their number of __________ - The elements in each column (_______) have the ____________ in their number of ___________
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1) The elements in each row (period) have a increase in their number of valence electrons 2) The elements in each column (groups) have the same number of valence electrons
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Elements are divided into three categories: 1) 2) 3) |
1) Metals, good conductors of heat and electricity 2) Non-metals, poor conductors of heat and electricity 3) Metalloids, properties intermediate between metals and non-metals
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The vertical groups have special names: 1A elements are what? 2A elements are what? 7A elements are what? 8A elements are what?
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1A elements are alkali elements 2A elements are alkaline earth metals 7A elements are halogens 8A elements are noble gases or rare gases
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-The group of elements from atomic number ___ to _____ are known as _______ -The group of elements from atomic number 57 to 71 are known as __________ - The group of elements from atomic number 89 to 103 are known as __________ |
1) The group of elements from atomic number 21 to 30 are known as transition metals 2) 57 to 71 are known as lanthanides or rare earths 3) 89 to 103 are known as Actinides
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Hybrid electric cars contain 10 kg of _________ in nickel-metal hydride batteries and smaller amounts of _________, _________ in electric motors and generators. ____________ is found in catalytic converters ______________ is used in magnets in electricity generating ________ and in magnets in computer disc drives ___________ is used in flat panel displays and compact fluorescent light bulbs |
1) Hybrid electric cars contain 10 kg of Lanthanum in nickel-metal hydride batteries and smaller amounts of neodymium, praseodymium in electric motors and generators 2) Cerium is found in catalytic converters 3) Neodymium is used in magnets in electricity generating windmills and in magnets in computer disc drives 4) Europium is used in flat panel displays and compact fluorescent light bulbs |
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Molecules - ___________ atoms held together by ___________ - atoms of the same elements or two or more ______________ - ________ neutral - diatomic molecules contain ____ atoms - polyatomic molecules contain ____ atoms |
1) two or more atoms held together by chemical forces or bonds 2) Atoms of the same elements or two or more elements joined in a fixed ratio 3) electrically neutral 4) diatomic molecules contain 2 atoms 5) polyatomic molecules contain greater than 2 atoms |
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Ions An atom or group of atoms with ___________ - ___________ or ______________ - results from ___________ or ___________ of electrons - if electrons are lost then the net charge is _________ (___________) - if electrons are gained then the net charge is __________ (______________) |
1) An atom or group of atoms with a net charge 2) positive or negative 3) results from gain or loss of electrons 4) If electrons are lost then the net charge is positive (cation +) 5) if electrons are gained then the net charge is negative (anion -)
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When an ion is formed the nucleus of the atom is __________ - __________ in the number of protons |
When an ion is formed the nucleus of the atom is not changed - no change in the number of protons |
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Ionic compounds - compounds formed by the combination of ___________ and ___________ - ________ tend to form ________ - _________ tend to form _________ - polyatomic atoms have combinations of ______________________ |
- Compounds formed by the combination of anions (-) and cations (+) - metals tend to form cations (+) - non-metals tend to form anions (-) - polyatomic atoms have combinations of two or more different atoms ex: OH- (hydroxide) , NH +4 (ammonium) |
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Chemical Formulas |
- composition of molecules and ionic compounds using chemical symbols - ratios in which elements are combined - molecular formulas - empirical formulas
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Molecular Formulas - Exact number __________ of each element in the _________________ of a substance - only use a subscript for ___________ - Molecular models such as __________ and _________ are used to visualize what a molecule might look like |
- Exact number of atoms of each element in the smallest unit of a substance ex : H20, CO2, NH3 - only use a subscript for > 1 atom - molecular models such as ball-and-stick model and space-filling are used to visualize what a molecule might look like
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Structural Formulas - Show how ______________________ in a molecule - chemical bonds are represented by ___________________________________
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- show how atoms are bonded together in a molecule - chemical bonds are represented by lines connecting atomic symbols |
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Empirical formulas -___________ chemical formula - shows __________________ - _____________________ of their atoms - not necessarily ________________________ in a given molecule |
- simplest chemical formula - shows which elements are present - simplest whole number ratio of their atoms - not necessarily the actual number of atoms in a given molecule Example : Hydrazine true or molecular formula: N2H4 Empirical formula: NH2
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Ionic compounds - Once ions are formed, the ______ will associate with the ______ to form a _________ - ionic compounds consist of ______________________ , but they are ______________________ |
- Once ions are formed, the cations will associate with anions to form an ionic compound - Ionic compounds consist of charged particles, but they are electrically neutral overall Ex: Na+ + Cl- -------> NaCl Mg ^2+ + 2 Cl- -----> MgCl2 2 Na+ + 0^2- -------> Na2O
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Ionic compounds - ionic compounds consist of _____________ bound to _____________ in a certain ratio - the formulas for ionic compounds can be predicted if ___________ - Many atoms produce ions with a particular _____ or _________ - Their position of the ______________ determines their charge |
- Ionic compounds consist of metal cations bound to non-metal anions in a certain ration - the formulas for ionic compounds can be predicted if the charges on the ions are known - many atoms produce ions with a particular (+) or (-) charge - Their position on the periodic table determines their charge |
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- Ionic formulas are always written as _________________ |
- Ionic formulas are always written as empirical formulas Ex: Ca 2+ + O 2- --------> CaO Not Ca2O2 |
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Naming ionic compounds - _________ are named 1st - generally the name of the __________ - Exceptions for ___________________ - ___________ are named second - Monatomic: change ending to ______ - Polyatomic: must know name of _____ |
- Cations are named 1st - generally the name of the element Ex: sodium, potassium, zinc - Exceptions for polyatomic cations Ex: ammonium (NH4+) - Anions are named second - Monatomic: change ending to "ide" - Polyatomic: must know name of ion |
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Examples of monatomic anions: - C4- : - Si4- : - N3- : - P3- : |
C4- : carbide Si4- : silicide N3- : nitride P3- : phosphide |
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Naming ionic compounds KBr K2O CaF2 AlCl3 Al2O3 ZnS |
KBr: potassium bromide K2O: potassium oxide CaF2: Calcium fluoride AlCl3: aluminum chloride Al2O3: aluminum oxide ZnS: zinc sulfide
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Iron can form __ different _______ - Fe2+ or iron (II) which is called _____ - Fe3+ or iron (III) which is called _______ - FeCl2 is called _____________________________ - FeCl3 is called ___________________________ Copper can form ___ different __________ - Cu + or copper(I) which is called _______ - Cu+2 or copper(II) which is called ________ |
Iron can form 2 different cations - Fe2+ or iron (II) which is called ferrous Fe3+ or iron (III) which is called ferric FeCL2 is called iron(II) chloride or ferrous chloride FeCl3 is called iron(III) chloride or ferric chloride Cu + or copper(I) which is called cuprous Cu2+ or copper(II) which is called cupric
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Compounds consisting solely of non-metals are __________________
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- Compounds consisting solely of non-metals are not ionic Exs: CS2, PCl3, NO, NO2
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Naming non-ionic compounds use prefixes such as mono-, di- , tri- , tetra-, penta- , to indicate __________ - change ending of second element name to _____ - Do not use the _____ prefix for the 1st element - the ____ in the prefix can be dropped |
Use prefixes such as mono-, di-, tri-, tetra-, penta-, to indicate the number of each element in the formula - change ending of second element name to "ide" - do not use the mono- prefix for the first element - the "a" in the prefix can be dropped ex: tetraoxide becomes textroxide |
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Naming Non-ionic compounds N2O NO2 NO N2O4 |
- N20 is dinitrogen monoxide - NO2 is nitrogen dioxide - NO is nitrogen monoxide - N2O4 is dinitrogen tetroxide |
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Acids - Substance that yields ____________________________ - formulas contain ________________________
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- substance that yields hydrogen ions (H+) when dissolved in water - formulas contain one or more hydrogen atoms and an anionic group |
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Naming simple acids - when the anion name ends in ______, the acid has the prefix _____ and the ending ____
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- when the anions name ends in "ide", the acid has prefix "hydro" and the ending "-ic" |
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Anion Corresponding Acid F- (fluoride) __________ Cl- (chloride) ____________ Br- (bromide) ___________ I- (iodide) _____________ CN- (cyanide) ___________ |
F- Fluoride = HF hydrofluoric acid Cl- Chloride = HCl hydrochloric acid Br- Bromide= HBr hydrobromic acid I- Iodide = HI hydroiodic acid CN- cyanide = HCN hydrocyanic acid
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Naming oxoacids acids that contain __________________________
HNO3 H2SO4 HClO3 H3PO4 |
- acids that contain hydrogen, oxygen, and another element (the central element)
HNO3 Nitric Acid H2SO4 Sulfuric Acid HClO3 Chloric Acid H3PO4 Phosphoric Acid
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Oxoacids can have the same central atom and a different number of ______ atoms - Adding 1 O changes ____ to ______ Ex: - Removing 1 O changes ____ to _____ Ex: - Removing 2 O changes ____ to ____ Ex: |
- Oxoacids can have the same central atom and a different number of oxygen atoms - adding 1 O changes -ic to per.......-ic Ex: HClO4 = perchloric acid - removing 1 O changes -ic to -ous Ex: HNO2 = nitrous acid - removing 2 O changes -ic to hypo.....ous Ex: HClO3 = hypochlorous acid
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