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Periodic Table. Mendeleev. Dmitri Mendeleev (1869, Russian) Organized elements by increasing atomic mass . Elements with similar properties were grouped together. There were some discrepancies. Mendeleev. Dmitri Mendeleev (1869, Russian)
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Mendeleev • Dmitri Mendeleev (1869, Russian) • Organized elements by increasing atomic mass. • Elements with similar properties were grouped together. • There were some discrepancies.
Mendeleev • Dmitri Mendeleev (1869, Russian) • Predicted properties of undiscovered elements.
Moseley • Henry Mosely (1913, British) • Organized elements by increasing atomic number. • Resolved discrepancies in Mendeleev’s arrangement.
Mendeleev’s Periodic Table Dmitri Mendeleev
The Periodic Table Period Group or Family Group or family Period
1 • Horizontal rows are called Periods or Series There are 7 periods 2 3 4 5 6 7
Vertical columns are calledGroups. • Elements are placed in columns by similar properties. • Also called families
Blocks • Main Group Elements • Transition Metals • Inner Transition Metals
8A 1A 2A 3A 4A 5A 6A 7A • The elements in the A groups are called the representative elements
These are called the inner transition elements and they belong here The group B are called the transition elements
Group 1A are the alkali metals • Group 2A are the alkaline earth metals
Group 7A is called the Halogens • Group 8A are the noble gases
Metallic Character • Metals • Nonmetals • Metalloids
The Properties of a Group: Alkali Metals • Easily lose valence electron • (Reducing agents) • React violently with water • Large hydration energy • React with halogens to form • salts
Examples of Metals Potassium, Kreacts with water and must be stored in kerosene Copper, Cu,is a relatively soft metal, and a very good electrical conductor. Zinc, Zn,is more stable than potassium Mercury, Hg, is the only metal that exists as a liquid at room temperature
Properties of Nonmetals Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element. • Nonmetals are poor conductors of heat and Electricity • Nonmetals tend to be brittle • Many nonmetals are gases at room temperature
Examples of Nonmetals Microspheres of phosphorus, P, a reactive nonmetal Sulfur, S, was once known as “brimstone” Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure
Properties of Metalloids Metalloids straddle the border between metals and nonmetals on the periodic table. • They have properties of both metals and nonmetals. • Metalloids are more brittle than metals, less brittle than most nonmetallic solids • Metalloids are semiconductors of electricity • Some metalloids possess metallic luster
Silicon, Si – A Metalloid • Silicon has metallic luster • Silicon is brittle like a nonmetal • Silicon is a semiconductor of electricity Other metalloids include: • Boron, B • Germanium, Ge • Arsenic, As • Antimony, Sb • Tellurium, Te
Periodicity Explained • Valence = Outer shell electrons • The orbitals fill up in a regular pattern • The outer shell electron configuration repeats • The properties of atoms therefore repeat when placed in order of Atomic Number
H 1 Li 3 Na 11 K 19 Rb 37 Cs 55 Fr 87 1s1 1s22s1 1s22s22p63s1 1s22s22p63s23p64s1 1s22s22p63s23p64s23d104p65s1 1s22s22p63s23p64s23d104p65s24d10 5p66s1 1s22s22p63s23p64s23d104p65s24d105p6 6s24f145d106p67s1
He 1s2 2 Ne 1s22s22p63s23p64s23d104p6 1s22s22p63s23p64s23d104p65s24d105p6 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p6 1s22s22p6 10 Ar 1s22s22p63s23p6 18 Kr 36 Xe 54 Rn 86
s- block s1 s2 • Alkali metals all end in s1 • Alkaline earth metals all end in s2 • really have to include He but it fits better later. • He has the properties of the noble gases.
Transition Metals - d block d4 d9 d1 d2 d3 d5 d6 d7 d8 d10
The p-block p1 p2 p6 p3 p4 p5
f6 f13 f1 f2 f3 f4 f5 f7 f8 f10 f12 f14 f11 f9 f - block • inner transition elements
Writing Electron configurations the easy way Yes there is a shorthand
Electron Configurations repeat • The shape of the periodic table is a representation of this repetition. • When we get to the end of the column the outermost energy level is full. • This is the basis for our shorthand.
The Shorthand • Write the symbol of the noble gas before the element. • Then the rest of the electrons. • Aluminum - full configuration. • 1s22s22p63s23p1 • Ne is 1s22s22p6 • so Al is [Ne] 3s23p1
More examples • Ge = 1s22s22p63s23p64s23d104p2 • Ge = [Ar] 4s23d104p2 • Hf = 1s22s22p63s23p64s23d104p65s2 4d105p66s24f145d2 • Hf=[Xe] 6s24f145d2
The Shorthand Again Sn- 50 electrons The noble gas before it is Kr Takes care of 36 Next 5s2 Then 4d10 Finally 5p2 [ Kr ] 5s2 4d10 5p2