Chemistry Science 09 Review!!
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Transcript of Chemistry Science 09 Review!!
Chemistry Science 09 Review!!
Science 10CT00D01
Topics from Science 09Atomic TheorySubatomic CompositionThe Periodic TableChemical BondingNomenclature and Chemical Reactions
Atomic Theory•Major Contributors:
• Dalton, Thomson, Rutherford, Bohr
John DaltonEngland, 1808Atomic Theory which states: An atom cannot be broken
down into smaller parts. Atoms of the same element
are exactly alike. Atoms of different elements
are different. Atoms can combine in
definite whole-number ratios to form compounds.
Dalton Model Diagram: Shading is used in the sphere to show
that it’s solid throughout. Every substance is made up of atomsAtoms are indestructible and indivisibleAtoms can neither be created or destroyed
J.J. ThomsonEngland, 1897Discovery Atoms contain
electrons Thomson found the
charge-to-mass ratio of an electron.
Thomson Model DiagramThis model is referred to as the ‘Plum Pudding model.’ Thomson believed that the atom consisted of a positive sphere (the pudding) with electrons embedded in it (the raisins).
+ +++
++
+
+
++++
+--
-
- -
-
--
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Ernest RutherfordNew Zealand, 1911Discovery Atoms are made up of mostly empty
space Atoms contain a small, dense, positively-
charged nucleus. • Gold Foil Experiment by Ernest Rutherford
• Positively charged radiation directed towards a thin sheet of gold foil
• Odd results: most radiation went through the foil, some scattered at wide angles, and some shot back at him!
+--
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Rutherford’s Model Diagram
+
Empty Space
Dense, positively charged nucleus
Niels BohrDenmark, 1913Discovery: Electrons contain specific
amounts of energy and orbit the nucleus in specific paths, call energy levels
Electrons must gain energy to move to a higher energy level or lose energy to move to a lower energy level
Bohr Model DiagramThe small particles in the center represent the protons and neutrons in the nucleus.
e-e-
e-Nucleus contains protons (+) and neutrons (o)
Electrons exist in energy levels, 2-8-8, then….
Subatomic Composition
•Atoms consist of: • Protons, neutrons, electrons
•Isotopes, ions, anions, cations
Three charges of an atom…
Mass of p & n are ~1000x greater than mass of e (making it insignificant)
First look at the Periodic Table: What do the numbers mean?
H1
0079.1
Atomic Number (p)Atomic Symbol
Ar (Relative At. Mass)For most common isotope, round it off. (For H would be 1 = 1p & 0n)
How many of each are there?
Protons: always the atomic #Electrons: same as p if neutral If -1, has one more e than p If +1, has one less e than p
Neutrons: Depends on isotope For most common, round off the atomic mass to
find the mass number, then use the formula Ar = p + nMass Number = protons + neutrons
Atomic Number
• Number of protons contained in an atom (p)
• Determines the element
• Every element of that kind has the same number of protons
Mass Number• Number of protons
and neutrons in an atom (p + n)
• Can change for various isotopes
Ions• Differing number
electrons (e)• Changes overall
charge• Cations (positive)• Anions (negative)
Isotopes• Differing number
of neutrons (n)• Changes Mass
Number
Isotopes• An isotope is an element that contains a
different number of neutrons and protons. Affects the molar mass of the element Longhand notation
• Element – Mass Number• Carbon – 12• Carbon – 14
Shorthand notation
XMass#
Atomic #
Charge
4126C
The Periodic Table•Layout: families, groups, etc•Trends:
• Atomic number, mass, valence, charge
• Electronegativity, ionization energy, atomic radius, reactivity, metallic property
H He
Li Be B C N O F Ne
Na
Mg Al Si P S Cl Ar
K Ca Se Ti V Cr Mn Fe Co Ni C
u Zn Ga Ge As Se
BrKr
Rb Sr Y Zr N
b Mo Tc Ru Rh Pd
Ag
Cd In Sn S
b Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au
Hg Tl Pb Bi P
oA
tR
n
Fr Ra Ac Rf Db Sg Bh Hs Mt D
s
Ce Pr Nd
Pm
Sm Eu Gd T
bD
yH
o Er Tm
Yb Lu
Th Pa U Np Pu A
mCm
Bk Cf Es F
mM
dN
o Lr
PERIODS - Similarities: The number of
outer electron shells.
H He
Li Be B C N O F Ne
Na
Mg Al Si P S Cl Ar
K Ca Se Ti V Cr Mn Fe Co Ni C
u Zn Ga Ge As Se
Br Kr
Rb Sr Y Zr N
b Mo Tc Ru Rh Pd
Ag
Cd In Sn S
b Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au
Hg Tl Pb Bi P
oAt
Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt D
s
Ce Pr Nd
Pm
Sm Eu Gd T
bDy
Ho Er T
mYb Lu
Th Pa U Np Pu A
mCm
Bk Cf Es F
mMd
No Lr
GROUPS – Similarities: The number of
electrons in the outer shell. Common reactivity, bonding, chemical and physical properties.
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Metaloids
Alkaline Earths
Alkali Metals
Transition Metals
Non-metals
Weak/Poor Metals
Halogens
Noble Gases
Actinides
Lanthanides
H He
Li Be B C N O F Ne
Na
Mg Al Si P S Cl Ar
K Ca Se Ti V Cr Mn Fe Co Ni C
u Zn Ga Ge As Se
BrKr
Rb Sr Y Zr N
b Mo Tc Ru Rh Pd
Ag
Cd In Sn S
b Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au
Hg Tl Pb Bi P
oA
tR
n
Fr Ra Ac Rf Db Sg Bh Hs Mt D
s
Ce Pr Nd
Pm
Sm Eu Gd T
bD
yH
o Er Tm
Yb Lu
Th Pa U Np Pu A
mCm
Bk Cf Es F
mM
dN
o Lr
METALIC PROPERTIES Similarities: An elements relative ability to conduct energy in the form of
heat or electricity.
the “stair”
Metals
Non metals
Metaloids
Valence Electrons
The number of electrons in the outer shell of an atom
1
2
2
1 2 3 54 6 7 8
1 2 3 54 6 7 8
2 2 2 2 2 2 2
2 2 2 2 2 2 2 28 8 8 88 8 8 8
Valence Electrons11+
2
2
2+3
3+4
4+ 53-
62-
71-
80
6
2
Periodic LawWhen the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties
Atomic RadiusA measure of the distance from the center of the nucleus to the outer-most electron (Bottom Left, Fr has
the largest Atomic Radius)Atomic Number vs. Atomic Radius
0
50
100
150
200
250
300
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49
Atomic Number
Ato
mic
Rad
ius
(pm
)
Series2
ElectronegativityAn atoms ability or affinity to gain another electron. Trend (Top right, excluding the noble gasses, F is
the most electronegative element)
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 10 20 30 40 50 60
Atomic Number
Elec
tron
egat
ivity
Series1
Table of Electronegativities
Ionization EnergyThe energy required to lose the
outer-most electron from an element. (Top right, He has the greatest
ionization energy)Atomic Number vs. Ionization Energy
0
500
1000
1500
2000
2500
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49
Atomic Number
Ioni
zatio
n En
ergy
(kJ/
mol
)
Series2
ReactivityAn atoms general ability to undergo a
chemical reaction. The Alkali Metals are the most electronegative
family/group. (Bottom Left, Fr is the most reactive)Highly reactive – readily
participates in chemical reactionsUn-reactive – does not readily participate in chemical reactionshttp://teachertube.com/viewVideo.php?video_id=41344&title=Alkali_Metals___Brainiac
Atomic Radius: A measure of the distance from the center of the nucleus to the outer-most electron Electronegativity: An atoms ability or affinity to gain another electron.Ionization Energy: The energy required to lose the outer-most electron from an element.Reactivity: An atoms general ability to undergo a chemical reaction.
Trends of the Periodic Table
4 major trends: top right or bottom left?
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Se Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Electronegativity (F) &
Ionization Energy
(He) Atomic Radius (F
r) & Reactiv
ity
(Fr)
Chemical Bonding
•Inter- vs Intra-molecular forces•Ionic vs Covalent
Molecular Interactions
Inter-molecular Forces Interaction between molecules that hold it
together in a network. Intra-molecular Forces Forces that hold groups of atoms together
and make them function as a unit
Intra-molecular Forces: Bonding Forces that hold groups of
atoms together and make them function as a unit.
Ionic bonds – transfer of electronsCovalent bonds – sharing of electrons
Metallic Bonding – sea of electrons
Which elements form which type of bond?
Metal / nonmetal = Ionic NaCl, MgBr2
Nonmetal / nonmetal = covalent CO2, CH4, H2O, NOGroup like metals = metalic Fe, Ti, Mg
Review: Why do atoms bond?
To satisfy the octet rule? Yes, but to be more specific, atoms
share electrons in order to complete their outer electron shell making them more stable as they are then in a lower state of energy.
But how do we know what type of bonding will occur between two atoms?
Metal Metalloids Nonmetals
I II III IV V VI VII VIII
Transition metals
Lewis Dot Diagrams
• Lewis Dot Diagrams are used in both ionic and covalent bonding
Simple Rules for BondingDuet Rule: H and He require 2 electrons for
stabilityOctet Rule: All other elements will have 8 valence
electrons for stabilityIn order to achieve this elements can steal (ionic) or share (covalent) electrons
Ions form when atoms lose or gain electrons.
Atoms with few valence electrons tend to lose them to form cations.
Atoms with many valence electrons tend to gain electrons to form anions
NeNNa F
Na+ N3- F-
O
O2-
Mg
Mg2+
Cations
Anions41
Ionic Bonds
Ionic bonds result from the attractions between positive and negative ions.
Ionic bonding involves 3 aspects:1. loss of an electron(s) by one element, 2. gain of electron(s) by a second element,3. attraction between positive and negative
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Ionic Bonds
Ionic Bonds Electrons are transferred
Electronegativity differences are
Greater than for covalent The formation of ionic bonds is
always exothermic!
A covalent/molecular bond is a chemical bond in which two or more electrons are shared by two atoms.Why should two atoms share electrons?
F F+
7e- 7e-
F F
8e-8e-
F F
F F
Lewis structure of F2
lone pairslone pairs
lone pairslone pairs
single covalent bond
single covalent bond
Covalent Bonds
8e-
H HO+ + OH H O HHor
2e- 2e-Lewis structure of water
Double bond – two atoms share two pairs of electrons
single covalent bonds
O C O or O C O
8e- 8e-8e-double bonds double bonds
Triple bond – two atoms share three pairs of electronsN N8e-8e-
N N
triple bondtriple bondor
Covalent Bonds
Linear
180o
Covalent Bonds
Trigonal Planar
120o
Covalent Bonds
Tetrahedral
109.5o
Covalent Bonds
Pyramidal (Tetrahedral)
107o
Covalent Bonds
Bent (Tetrahedral)
104.5o
Covalent Bonds
Boron Trifluoride Non-Polar (even)
F
B
F F
Trigonal planar shape: BF3 violates the octet rule
Covalent Bonds
..H N H
H
Ammonia NH3 – Polar (uneven)
Covalent Bonds
Trigonal Bipyramidal / Octahedral
120o
90o 90o
90o
Covalent Bonds
Explain intra/inter molecular bonding, the difference between covalent/ionic bonds, how you determine bonding type, and types of bonds:
Review……Covalent Bonds
Chemical Reactions & Nomenclature•Nomenclature for
• Ionic, covalent, acids•Types of Chemical Reactions•Balancing
Look at the First Element!!A metal = MUST BE IONIC Does it have a polyatomic? Does it have a transition metal?A nonmetal = MUST BE COVALENTHydrogen = MUST BE AN ACID Binary Acid? Oxoacid (Polyatomic)?
first element Metal = IonicNO prefixesThe simplest whole number ratio is generally the ionic formula. (empirical formula)
BinaryNaClMgBr2
Li2S
Polyatomic
Na2CO3
Mg(NO3)2
Li3PO4
TransitionFeCl3
Ni3(PO3)2
ZrSO4
Polyatomic Ions(Common 11)
PO43- PO3
3- OH-
NO2- NO3
- NH4+
SO32- SO4
2- CO32-
ClO3- ClO2
-
First element nonmetal = Covalent
Greek Prefixes Mono (1), di (2), tri (3), tetra (4), penta (5),
etc…. First nonmetal keeps element name Change ending of second nonmetal to –ide
P2O5 CCl4 CO2 COSiO2
NO2 CF4 SF6 PF5NO
First element hydrogen = Acid
BinaryH and another
elementUse hydro- prefix
Use –ic suffixHCl HFHBrH2S HI
Oxoacid / PolyH and 2 or more
NO prefixIf poly –ate -ic If poly –ite -ous
HNO3 H3PO4
H3PO3 H2SO4
Reaction TypesSynthesis/Composition (A + B AB)Decomposition (AB A + B)Single Replacement (A + BC B + AC)Double Replacement (AB + CD CB + AD)Combustion (CxHy + O2 CO2
+ H2O)
Balancing EquationsConservation of MassThere must be the same amounts of each element on each side
__ C3H8 + ___ O2 ___ CO2 + ___ H2O___ KClO3 ___ KCl + ___ O2
__ N2O3 + __ H2O __ HNO2