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The Periodic Table
History
• End 1700’s – ca. 30 elements• Middle 1800’s – ca. 62 elements• Today – 109+ elements• How did we get there?• How did we arrange these elements?• Who arranged these elements?• We will answer all of these questions and
more in the following classes!!
J.W. Dobereiner• How did Li, Na, and K act?• What do you know about He, Ne, and Ar?• Classified elements in groups of THREE!• Called these groups TRIADS• Grouped elements into triads (grps of 3)• Cl Ca Li• Br Sr Na• I Ba K
• Usually the middle element containing a property
that falls in between the 1st and 3rd
– Density– Atomic Mass
• Take a look at Cl, Br and I
J.A.R. Newlands
• Arranged elements in order of INC. Atomic Mass
• Noticed that 8th element shared properties of 1st and 9th element shared prop. of 2nd • Pattern repeats every 8 elements• OCTAVES
Mendeleev!! (Meyer)
• Considered Father of the P.T.• Flash Cards• Arranged by INC. Atomic Mass• Produced first P.T.• Grouped elements according to
properties
Mendie, You’re Wrong!!
• Mendeleev broke the law of octaves• Wanted to keep elements with same prop.
together (same columns) • “Sorry to say my fellow scientists BUT, some of
these atomic masses are incorrect! And, there are elements out there that we have not discovered yet.”– Two very bold statements!!
Germanium is located below silicon. Mendeleev predicted its properties based on its location in
his table.Ekasilicon (Es) Germanium (Ge)
1. Atomic mass: 72 1. Atomic mass: 72.61
2. High melting pt. 2. Melting pt: 945° C
3. Density: 5.5g/cm3 3. Density: 5.323g/cm3
4. Dark gray metal 4. Gray metal
5. Will obtain from K2EsF6
5. Obtain from K2GeF6
6. Will form EsO2 6. Forms oxide (GeO2)
Its Periodic Law
• Even though masses were recalculated there were some elements that were still out of order
• This was due to a prop. that had yet to be discovered
• Periodic law – The physical and chemical properties of the elements are periodic functions of their atomic numbers.
Henry Moseley
• Developed the concept of Atomic Number• Worked in Rutherford’s Lab as a Post-doc.• Metals produce x-rays when hit with e-
• Frequencies differed for each metal• Different frequencies came from the amount
of pos. charge in the Nucleus
???
• Why is Mendeleev and not Newlands or Moseley considered the Father of the P.T.?
Dalton’s Periodic Table
Alternative Periodic Tables
The Periodic Table
Organization
Organization of the Periodic Table:
• Rows on the periodic table are called PERIODS
• Columns on the periodic table are called GROUPS or FAMILIES
The P.T. can be broken up into…
• 7 periods or rows
• 18 groups or families
• 4 blocks (s p d f)
hggfgggyuhyrftgyhyu
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Periods and Blocks
• In period 1, which sublevels are being filled?• 1S (H -1S1 … He – 1S2)• In period 2, which sublevels are being filled?• 2S followed by 2P • What factor determines the length of each
period?• The sublevels being filled and the number of
electrons necessary to fill them.
Remember…Sublevel and e- capacity s 2 p 6 d 10 f 14
S Block Elements• Contains elements in Group 1, Group 2, and
He from Group 18.• End in similar e- config. (ns1 or ns2)• Group 1 is called the ???• Alkali Metals• Do you think these can be found freely in
nature?• Group 2 is called the ???• Alkaline Earth Metals• Do you think these can be found freely in
nature?
Alkali Metals• Soft
• Very reactive (react with water!)• Always found combined in
nature• Form +1 ions• Cesium is the most reactive of
the common alkali metals
Lithium pellets coated in lithium oxide
Lithium and Sodium stored under mineral oil
K flame
Technically, francium is the most reactive and least common alkali metal, but since it is highly radioactive with an estimated 550 grams in the entire Earth’s crust at one time, its abundance can be considered zero in practical terms.)
Cesium
1 1H
2 3Li
3 11Na
4 19K
5 37Rb
6 55Cs
7 87Fr
Alkaline Earth Metals
• Less reactive than alkali metals (react with acid)
• Form +2 ions
Due to its small nucleus, Be is highly transparent to X-rays and can be used as a barrier “window” between a vacuum chamber and an x-ray microscope.
Mg can be used as a fire starter.
Radium paint was used in the mid 1900s to paint the hands and numbers of some clocks and watches. The paint was composed of radium salts and a phosphor and glowed in the dark.
2 4Be
3 12Mg
4 20Ca
5 38Sr
6 56Ba
7 88Ra
D Block Elements• The elements in the d – block are referred to
as ….• Transition elements or transition metalsQ - What are some typical properties of
transition metals?A – good conductors of electricity, high luster,
less reactive than group 1 and 2. Some are so un-reactive they do not form compounds! (platinum and gold for ex.)
Transition Metals• Less reactive than
groups 1 and 2• Form ions with a range
of charges (+1 to +7) • Many will form colored
solutions when dissolved
From left to right, aqueous solutions of: Co(NO3)2 (red); K2Cr2O7 (orange); K2CrO4 (yellow); NiCl2 (green); CuSO4 (blue); KMnO4 (purple).
Co glass
P Block Elements• Contains elements in Group 13, Group 14,
Group 15, Group 16, Group 17, and the remaining elements from Group 18 (except He)
• Group 16 is known as the???• Group 17 is known as the???• Group 18 is known as the???
Oxygen Family (Chalcogens)• Somewhat
Reactive• Can gain 2
electrons• Form -2 ions
Liquid O2
Sulfur melts to a blood-red liquid. When burned, it emits a blue flame.
selenium
2 8O
3 16S
4 34Se
5 52Te
6 84Po
7 116Uuh
O2(s) very reactive
Halogens• Group 17
• Very reactive nonmetals
• Form -1 ions• Form diatomic
compounds (Cl2, F2, Br2…)• F2 and Cl2 gases
Group 17 is the only group that exhibits all three states of matter.
CaF2
fluorite
2 9F
3 17Cl
4 35Br
5 53I
6 85At
7 117Uus
C4H8Cl2S
Noble Gases
• Group 18• Do not react easily• Do not form ions• The non-reactivity is
why the gases are called inert
Group 18
Period
1 2He
2 10Ne
3 18Ar
4 36Kr
5 54Xe
6 86Rn
7 118Uuo
F Block Elements
• The f-block contains elements from the inner transition metals (rare earth elements).
• Outer electrons are found in the f – orbital's.
• Contains the Lanthanides and Actinides
Rare Earth Metals
• These metals have very similar properties and are difficult to separate
• Found in small quantities in nature
• The Actinium series are all radioactive
Rare Earth Metals
uranium
Am-241
A ring of weapons-grade electrorefined plutonium, with 99.96% purity. This 5.3 kg ring is enough plutonium for use in a modern nuclear weapon.
Other “gangs” of elements are also present on the P.T.
Metalloids
Q - Which elements are included?A – B, Si, Ge, As, Sb, Te, At
Q – PropertiesA – brittle solids with properties in between
metals and non-metals.
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Metal Groups
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Basic Properties of Metals, Nonmetals, and Metalloids
• Metals:1. malleable, ductile and shiny solids.2. Conduct heat and electricity well.
3. Tend to give up electrons in reactions.• Nonmetals:
1. Generally gases or brittle solids.2. Solids have dull surface.3. Good insulators.
4. Tend to gain electrons in reactions.• Metalloids:
1. Properties of both metals and nonmetals.
Throw it all together and you get…
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