Arranged the elements by increasing atomic mass and noticed properties repeat regularly Left a space if an element didnt belong in a particular column THE PERIODIC TABLE 1H1 of 10 Mendeleev stated the ID: 203772
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Slide1
1869 DMITRI MENDELEEVArranged the elements by increasing atomic mass, and noticed properties repeat regularlyLeft a space if an element didn’t belong in a particular column
THE PERIODIC TABLE
1H-1 (of
14)Slide2
Mendeleev stated the PERIODIC LAW
:The properties of the chemical elements are not arbitrary, but vary with their atomic masses in a systematic wayMendeleev was able to predict properties of undiscovered elements
However, accurate atomic mass determinations showed errors in the table
1H-2 (of
14)
THE PERIODIC TABLESlide3
1912 HENRY MOSELEYMeasured the frequency of x-rays from excited atoms Found they were proportional to the ATOMIC NUMBER of the atoms, not the atomic mass
1H-3 (of
14)Slide4
1912 HENRY MOSELEYThis work changed the PERIODIC LAW:The properties of the chemical elements vary with atomic number
1H-4 (of
14)Slide5
PERIOD or SERIES – A row
GROUP or FAMILY – A column
Elements in columns have similar properties because they have the same number of valence electrons
1H-5 (of
14)Slide6
PERIODIC TRENDS OF ATOMS
They involve the
attraction of either
(1)
outer shell electrons or (2) free electrons to the nucleus of an atom, and depend on
(1) The number of protons in nucleus
(2) The number of energy levels blocking or
SHIELDING
the nucleus from the outer shell or free electrons
1H-6 (of 14)Slide7
1) ATOMIC RADIUS – The distance from the nucleus to the outer shell of an atom
1H-7 (of
14)Slide8
PERIODIC TRENDS IN ATOMIC RADII
Period – The atomic radii
decrease moving to the right the outer shell electrons are attracted by an
increasing nuclear charge, while the shielding of the nuclear charge remains the sameGroup – The atomic radii increase moving down a column
even though the nuclear charge is increasing, the outer shell electrons are more shielded from the nuclear charge
Atom with the largest atomic radius ?
Atom
with the smallest atomic radius?
1H-8 (of
14)
Fr
HeSlide9
1H-9 (of
14)Slide10
Radii
V (Z = 23) 0.122 nm Nb (Z = 41)Ta (Z = 73)
EXCEPTIONS TO THE TRENDS IN ATOMIC RADII
Group
Atoms in the 5d sublevel section of the periodic table are not larger than atoms in the 4d sublevel section
0.134 nm
This is called the LANTHANIDE CONTRACTION
1H-10
(of
14)
0.134 nm
Increasing Decreasing
Factor Factor
1 more EL 18 more p
+
1 more EL
32 more p
+
Slide11
2) IONIZATION ENERGY (IE) – The energy change for the removal of an electron from a gaseous atom
X (g)
→ X+ (g) + e-
Endothermic – A process in which energy is absorbed (∆E is positive)
Exothermic – A process in which energy is released (∆E is negative) Ionization Energies are always endothermic
1H-11
(of
14)Slide12
SUCCESSIVE IONIZATION ENERGIES
Mg
(g)
→ Mg
+
(g) + e-
1
st
IE = 736 kJ/mol
Mg
+
(g)
→ Mg
2+
(g)
+ e
-
2
nd
IE = 1,451 kJ/mol
Mg
2+
(g)
→ Mg
3+
(g)
+ e
-
3
rd
IE = 7,728 kJ/mol
Mg
3+
(g)
→ Mg
4+
(g)
+ e
-
4
th
IE = 10,534 kJ/mol
Successive ionization energies always increase because successive ions have less e
-
-e
-
repulsion
1H-12
(of
14)Slide13
SUCCESSIVE IONIZATION ENERGIES
Mg
(g)
→ Mg
+
(g) + e-
1
st
IE = 736 kJ/mol
Mg
+
(g)
→ Mg
2+
(g)
+ e
-
2
nd
IE = 1,451 kJ/mol
Mg
2+
(g)
→ Mg
3+
(g)
+ e
-
3
rd
IE = 7,728 kJ/mol
Mg
3+
(g)
→ Mg
4+
(g)
+ e
-
4
th
IE = 10,534 kJ/mol
Successive ionization energies always increase because successive ions have less e
-
-e
-
repulsion
7,728 kJ/mol
10,534 kJ/mol
Small ionization energies occur when removed e
-
s are valence e
-
s, which are the most shielded from the nuclear charge
1H-13
(of
14)Slide14
Determine which atom is sodium and which atom is aluminum
1
st
IE = 578 kJ/mol
2
nd
IE = 1,817 kJ/mol
3
rd
IE = 2,745 kJ/mol
4
th
IE = 11,577 kJ/mol
1
st
IE = 496 kJ/mol
2
nd
IE = 4,562 kJ/
mol
3
rd
IE = 6,912 kJ/mol
4
th
IE = 9,543 kJ/mol
Na
Al
Atom 2
Atom 1
1H-14
(of
14)Slide15Slide16
PERIODIC TRENDS IN 1st IONIZATION ENERGIES
Period – The 1st IE increases moving to the right the removed electron is attracted by an increasing nuclear charge, while the shielding of the nuclear charge remains the same
Group – The 1st IE decreases moving down a column even though the nuclear charge is increasing, the removed electron is more shielded from the nuclear charge
Atom with the highest 1
st
IE ?He
Atom with the lowest 1
st
IE?
Fr
1I-1
(of
19)Slide17
1I-2
(of 19)Slide18
EXCEPTIONS TO THE TRENDS IN 1st IONIZATION ENERGIESPeriod
Li Be B C N O F Ne
519 900 1088 1406 1682 2080
519 900
799
1088 1406
1314
1682 2080
1s 2s 2p
B
↑↓ ↑↓
↑
___ ___ ___ ___ ___
The removed e
-
for B is in a p orbital, whereas the removed e
-
for Be is in an s orbital - e
-
s in p orbitals are more shielded from the nuclear charge than e
-
s in s orbitals
1I-3
(of
19)Slide19
EXCEPTIONS TO THE TRENDS IN 1st IONIZATION ENERGIESPeriod
Li Be B C N O F Ne
519 900
799
1088 1406
1314
1682 2080
The removed e
-
for O is paired and experiencing e
-
-e
-
repulsion, whereas the removed e
-
for N is not
↑↓ ↑↓ ↑
↓
↑ ↑
___ ___ ___ ___ ___
O
1s 2s 2p
1I-4
(of
19)Slide20
3) ELECTRON AFFINITY (EA) – The energy change for the addition of an electron to a gaseous atom
X (g) + e-
→ X- (g)
Electron Affinities are always exothermic
1I-5
(of
19)Slide21
PERIODIC TRENDS IN ELECTRON AFFINITIESPeriod – EA
decreases (becomes more exothermic) moving to the right a free electron is attracted by an increasing nuclear charge, while the shielding of the nuclear charge remains the same (except noble gases)
Group – EA increases (becomes less exothermic) moving down a column even though the nuclear charge is increasing, a free electron is more shielded from the nuclear charge
1I-6
(of
19)Slide22
1I-7
(of 19)Slide23
EXCEPTIONS TO THE TRENDS IN 1st ELECTRON AFFINITIESGroup In the p block of the periodic table, adding e-
s to small atoms (those in the 2nd period) results in large e--e- repulsion, so their 1st EA’s are slightly less exothermic than atoms in the 3rd period
F
Cl -349 kJ/
mol
Br -343 kJ/molI -295 kJ/mol
-328 kJ/
mol
← element with the
most exothermic EA
1I-8
(of
19)Slide24
EXCEPTIONS TO THE TRENDS IN 1st ELECTRON AFFINITIESPeriod
K Ca Ga Ge As Se Br Kr
-49 -76 -116 -195 -325
-49
~0
-76 -116
-75
-195 -325
~0
The added e
-
will go into an orbital of a new sublevel, where it will be very shielded from the nuclear charge
↑↓
___ ___ ___ ___
___ ___
___ ___ ___
Ca [Ar]
4s 3d 4p
↑↓ ↑↓
↑↓
↑
↓ ↑↓ ↑↓
↑↓
↑↓ ↑↓
___ ___ ___ ___
___ ___
___ ___ ___
Kr [Ar]
1I-9
(of
19)Slide25
EXCEPTIONS TO THE TRENDS IN 1st ELECTRON AFFINITIESPeriod
K Ca Ga Ge As Se Br Kr
-49
~0
-76 -116
-75
-195 -325
~0
The added e
-
will experience e
-
-e
-
repulsion
↑↓ ↑↓
↑↓
↑
↓ ↑↓
↑↓
↑ ↑
↑
___ ___ ___ ___
___ ___
___ ___ ___
As [
Ar
]
4s 3d 4p
1I-10
(of
19)Slide26
EXCEPTIONS TO THE TRENDS IN 1st ELECTRON AFFINITIESPeriod
K Ca Ga Ge As Se Br Kr
-49
~0
-76 -116
-75
-195 -325
~0
What other two elements in the 4
th
period would you expect to have
less exothermic EA’s than the element before them?
Mn
and Zn
1I-11
(of
19)Slide27
METALS
Physical Properties – Low number of valence electrons, metallic luster, malleable, ductile, conductors of heat
and electricity, form water solutions that are basicSolids are brilliant white (or silver) except copper (red) and gold (yellow), mercury is a liquidChemical Properties – Due to the low ionization energies of their valence electrons, they can lose their valence electrons to produce positive ions (called CATIONS)
1I-12
(of
19)Slide28
Group 1 - Alkali Metals
Group 2 - Alkaline Earth Metals
Group 11 - Coinage Metals
8, 9, 10 - Fe-Co-Ni Triad - The Ferromagnetic Metals
8, 9, 10 - Noble Metals (Ru, Rh, Pd, Os, Ir, Pt)d Block - Transition Metalsf Block - Inner Transition Metals (Lanthanides and Actinides)
1I-13
(of
19)Slide29
Metal Hardness
Group 1 metals are soft, hardness increases to Group 6, and then hardness decreases to Group 16
1I-14
(of
19)Slide30
Metal Activity
Group 1 metals are extremely active, and activity decreases to Group 11, with the Noble Metals, Coinage Metals, and Hg being very inactive
Al and Zn are very active, and activity decreases down and to the right
1I-15
(of
19)Slide31
NONMETALS
Physical Properties – High number of valence electrons, opposite of
metals, form acidic water solutions
Some are crystalline solids, bromine is a liquid, and some are gases
Chemical Properties – Due to their highly exothermic electron affinities, they can gain electrons until their outer shells are full to produce negative ions (called ANIONS)
1I-16
(of
19)Slide32
Group 18 - Noble Gases
Group 17 - Halogens
Hydrogen - A group of its own in that it can form 1+ and 1- ions
1I-17
(of
19)Slide33
Nonmetal Activity
Group 17 nonmetals are extremely active, and activity decreases down and to the left
H is active, and the Noble Gases are inert
1I-18
(of
19)Slide34
METALLOIDS
Intermediate number of valence electrons, properties of metals and nonmetals
1I-19
(of
19)Slide35Slide36
Hydrogen - Colorless gas (H2)Helium - Colorless gas (He)
1J-1
(of
5)Slide37
ALLOTROPES – Forms of an element with different interatomic bonding, so different properties
Boron - Crystalline brownCarbon - Crystalline as diamond, graphite, or
buckminster-fullerene; amorphous as charcoal
1J-2
(of
5)Slide38
Nitrogen - Colorless gas (N2)Oxygen - Colorless gas allotropes dioxygen (O2) and ozone (O3)Phosphorus - Crystalline red, white (P4), and black allotropes Sulfur - Crystalline yellow (S8 rings) and other allotropes (S8 chains)
1J-3
(of
5)Slide39
Fluorine - Pale yellow-green gas (F
2)Chlorine - Yellow-green gas (Cl2)
Bromine - Orange liquid (Br2)Iodine - Crystalline black (I2), sublimes to violet vaporNoble Gases - Colorless monatomic gases
1J-4
(of
5)Slide40
Bismuth (Z = 83) – The element of highest atomic number with at least one stable isotope
Plutonium (Z = 94) – The element of highest atomic number found naturally on Earth
1J-5
(of
5)Slide41
REVIEW FOR TEST 1Metric SystemDimensional AnalysisSignificant FiguresScientists
and their WorkDalton’s Atomic TheoryElectromagnetic RadiationPhotonConversions from Wavelength to Frequency to
EnergySlide42
REVIEW FOR TEST 1Bohr Model of the AtomBohr Orbit EnergyElectronic Energy Diagram
Electron Transition and Ionization EnergiesSlide43
REVIEW FOR TEST 1Schrodinger Electron Wave ModelOrbitalElectrons per Energy Level, Sublevel, Orbital
Orbital NotationElectron Configuration NotationElectron Dot NotationElectron Filling PatternEffects of Shielding on the Electron Filling PatternExceptions to the Electron Filling
PatternSlide44
REVIEW FOR TEST 1Atomic NumberIsotopesMass NumberStable and Radioactive Isotopes
Half-LifeFusionFissonOrigin of AtomsAtomic Mass
Molar MassConversions from Atoms to Moles to MassSlide45
REVIEW FOR TEST 1Period, Series
Group or FamilyAtomic Radii Trend and ExceptionsIonization Energy
Energy Equation Trend and Exceptions Successive Ionization EnergiesElectron Affinity
Equation Trend and ExceptionsSlide46
REVIEW FOR TEST 1Metals
Trends in Physical and Chemical Properties Ion ChargesNonmetals
Trends in Physical and Chemical Properties Ion ChargesMetalloidsDescriptions of Elements
AllotropesExperiments 1-5