The Periodic Table
Chemistry
Stanislao Cannizzaro (1826-1910)Stanislao Cannizzaro (1826-1910)
•Found a method to determine atomicmass•Found a method to determine atomicmass
Dimitri Mendeleev (1834-1907)Dimitri Mendeleev (1834-1907)
•“Father of the Periodic Table”•“Father of the Periodic Table”
•Made the first accepted Periodic Table•Made the first accepted Periodic Table
•Noticed trends and left empty spaces for“missing” elements•Noticed trends and left empty spaces for“missing” elements
**By 1860 more than 60 elements were known****By 1860 more than 60 elements were known**
Henry Moseley (1887 – 1915)Henry Moseley (1887 – 1915)
•Found a method to determine atomic number(# of protons)•Found a method to determine atomic number(# of protons)
Periodic Law
•Properties of elements are based on atomicnumber and valence electrons•Properties of elements are based on atomicnumber and valence electrons
The Modern Periodic Table
•Arranged by increasing atomic number soelements with similar properties fall in the samecolumns
•Newest sections added: Lanthanides, Actinides,Noble Gases
Valence Electrons:Valence Electrons:
•Outer Shell Electrons•Outer Shell Electrons
•Have the Highest Principle Quantum Number•Have the Highest Principle Quantum Number
•Determine many properties of the atoms•Determine many properties of the atoms
•Were the “dots” on the dot diagram from lastchapter!•Were the “dots” on the dot diagram from lastchapter!
Periodic Table Arrangement:
Period
# ofElements
EnergySublevel
Max # ofElectrons
1
2
s
2
2
8
s,p
8
3
8
s,p
8
4
18
s,p,d
18
5
18
s,p,d
18
6
32
s,p,d,f
32
7 (iffinished)
32
s,p,d,f
32
Using only the ELECTRON CONFIGURATION…Using only the ELECTRON CONFIGURATION…
Example:
1s22s22p63s23p64s23d104p3
Located in PERIOD 4
Highest Principle QN
Using only the Electron Configuration…Using only the Electron Configuration…
Example:
1s22s22p63s23p64s23d104p3
Located in Group 15 – Add theelectrons from the highest period(includes s, d if any, and p if any)
s – Block
•Group 1 = Alkali Metals•Group 1 = Alkali Metals
SoftSoft
Extremely reactiveExtremely reactive
(but…Hydrogen is NOT a metal)(but…Hydrogen is NOT a metal)
1 valence electron1 valence electron
![MCj04347780000[1]](data/images/img15.png)
![MCj04347780000[1]](data/images/img16.png)
![MCj03256440000[1]](data/images/img17.png)
s-Block
•Group 2 = Alkaline-Earth Metals•Group 2 = Alkaline-Earth Metals
2 valence electrons2 valence electrons
Reactive but less than Group 1Reactive but less than Group 1
![MCj04347780000[1]](data/images/img19.png)
p block:p block:
•Groups 13-18•Groups 13-18
•Properties vary greatly•Properties vary greatly
(due to “steps”)(due to “steps”)
•Valence Electrons =•Valence Electrons =
Group # - 10Group # - 10
•Example:•Example:
p block:p block:
•Group 17 = Halogens•Group 17 = Halogens
Very reactiveVery reactive
![MCj03256440000[1]](data/images/img22.png)
A halogen lamp also uses a tungsten filament, but it is encasedinside a much smaller quartz envelope. Because the envelopeis so close to the filament, it would melt if it were made fromglass. The gas inside the envelope is also different -- it consistsof a gas from the halogen group. These gases have a veryinteresting property: They combine with tungsten vapor. If thetemperature is high enough, the halogen gas will combine withtungsten atoms as they evaporate and redeposit them on thefilament. This recycling process lets the filament last a lotlonger. In addition, it is now possible to run the filament hotter,meaning you get more light per unit of energy. You still get a lotof heat, though; and because the quartz envelope is so close tothe filament, it is extremely hot compared to a normal light bulb.A halogen lamp also uses a tungsten filament, but it is encasedinside a much smaller quartz envelope. Because the envelopeis so close to the filament, it would melt if it were made fromglass. The gas inside the envelope is also different -- it consistsof a gas from the halogen group. These gases have a veryinteresting property: They combine with tungsten vapor. If thetemperature is high enough, the halogen gas will combine withtungsten atoms as they evaporate and redeposit them on thefilament. This recycling process lets the filament last a lotlonger. In addition, it is now possible to run the filament hotter,meaning you get more light per unit of energy. You still get a lotof heat, though; and because the quartz envelope is so close tothe filament, it is extremely hot compared to a normal light bulb.
p block:p block:
•Group 18 = Noble Gases•Group 18 = Noble Gases
Very unreactiveVery unreactive
They have a stable (full) valence octetThey have a stable (full) valence octet
Many used in creating signsMany used in creating signs
![MCj03256440000[1]](data/images/img29.png)
Neon signs are luminous-tube signs thatcontain neon or other inert gases at a lowpressure. Applying a high voltage (usually a fewthousand volts) makes the gas glow brightly.They are produced by the craft of bending glasstubing into shapes. A worker skilled in this craftis known as a glass bender, neon or tubebender.
d block:d block:
•Groups 3-12•Groups 3-12
•Called the TRANSITION METALS•Called the TRANSITION METALS
•Luster, conductive, Malleable, Ductile•Luster, conductive, Malleable, Ductile
•Hg is the ONLY liquid metal•Hg is the ONLY liquid metal
![MCj04260680000[1]](data/images/img31.png)
f Block
Lanthanides
Actinides
“Trends”
Strength of Nucleus
A.Across a period – strength gets stronger
Atomic Number!! More protons = greater charge onnucleusAtomic Number!! More protons = greater charge onnucleus
B. Down a group – strength gets weaker
Size of atom is getting larger – e- in levels fartheraway – shielding attraction from nucleusSize of atom is getting larger – e- in levels fartheraway – shielding attraction from nucleus
Atomic Radius (size of atom)
A.Across a period – radius gets smaller
Decreases across periods because of increasingpositive chargeDecreases across periods because of increasingpositive charge
e- are pulled closer to a higher charged nucleuse- are pulled closer to a higher charged nucleus
Increased pull results in a smaller atomic radiusIncreased pull results in a smaller atomic radius
B.Down a group – radius gets bigger
Outer e- fill an s sublevel in a higher energy levelfarther from the nucleusOuter e- fill an s sublevel in a higher energy levelfarther from the nucleus
Energy to REMOVE an electronIonization Energy - Energy to REMOVE an electron
•ION – atom that has gained or lost an electron•ION – atom that has gained or lost an electron
A.Across a period – ionization energy increasesA.Across a period – ionization energy increases
Increasing nuclear charge – pulls e- toward nucleusIncreasing nuclear charge – pulls e- toward nucleus
Harder to pull away because of strong attractionHarder to pull away because of strong attraction
B. Down a group – ionization energy decreasesB. Down a group – ionization energy decreases
Outer e- are farther away from nucleus – more easilyremoved.Outer e- are farther away from nucleus – more easilyremoved.
Outer e- are also shielded from positive nucleus – weakattraction – easily removedOuter e- are also shielded from positive nucleus – weakattraction – easily removed
Electron Affinity –
•Energy change when an electron is ADDED•Energy change when an electron is ADDED
When EASY to add an electron – EA is EXOTHERMIC /NEGATIVEWhen EASY to add an electron – EA is EXOTHERMIC /NEGATIVE
When DIFFICULT to add an electron – EA is ENDOTHERMIC /POSITIVEWhen DIFFICULT to add an electron – EA is ENDOTHERMIC /POSITIVE
A.Across a period – EA is easier/more exothermicA.Across a period – EA is easier/more exothermic
B.Down a group – EA is difficult/more endothermicB.Down a group – EA is difficult/more endothermic
FYI - Generally more difficult to add e- to larger atoms!!FYI - Generally more difficult to add e- to larger atoms!!
Ionic Radius
•Size of ion
•Same trend as atomic radius:
Across a period – gets smaller
Down a group – gets bigger
Ionic Radius
•Size of ion
•Cation – Lost electrons
Positively charged ion
due to less electrons, so nucleuscan pull better on each e-Smaller than neutral atom; due to less electrons, so nucleuscan pull better on each e-
Potassium Atom
Potassium ION
Ionic Radius
•Size of ion
•Anion – Gained electrons
Negatively charged ion
due to more electrons, so nucleuscan’t pull as well on each e-Larger than neutral atom; due to more electrons, so nucleuscan’t pull as well on each e-
Electronegativity
•Ability to attract electrons
A.Across a period – EN increases
B.Down a group – EN decreases
FYI:
Nonmetals are always more electronegative!!Nonmetals are always more electronegative!!
Larger atoms attract e- less stronglyLarger atoms attract e- less strongly
Which is smaller – C or O?Which is smaller – C or O?
Which is larger – Be or Be+2 (Neutral Beatom or Be ion)?Which is larger – Be or Be+2 (Neutral Beatom or Be ion)?
Which has a more exothermic electronaffinity – Na or P?Which has a more exothermic electronaffinity – Na or P?
Which has a more endothermic electronaffinity – K or Cs?Which has a more endothermic electronaffinity – K or Cs?
Which has a higher ionization energy – Gaor Se?Which has a higher ionization energy – Gaor Se?
Which has a higher electronegativity – F orBr?Which has a higher electronegativity – F orBr?