chem unit3
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Element TimelineAntiquity: Au, Ag, Cu, Fe, Pb, Sn, Hg, C, S
Before 1735: As, P, Sb, Zn
1735 – 1745 Co, Pt
1745 – 1755: Ni, Bi
1765 – 1775: H, O, N, Cl, Mn
1775 – 1795: Mo, W, Te, U, Sr, Ti, Y
1795 – 1805 : V, Cr, Be, Nb, Ta, Ce, Pd, Os, Rh, Ir
1805 – 1815: Na, K, Ba, Ca, Mg, I, B
Dobereiner’s Triads
7 + 39 = 23 2
For Li, Na and K
deChantcourtois’ Spirals
Newlands’ Octaves
Mendeleev (1869)
Lothar Meyer
Mendeleev’s Gaps
Henry Moseley
Organized according to atomic number rather than atomic mass
Periodic Table
Periodic Table
Periodic Table Families
Alkali Metals
3 electrons
11 electrons
19 electrons
37 electrons
55 electrons
87 electrons
Alkali Metals
1s2 2s1
1s22s22p6 3s1
1s22s22p63s23p6 4s1
1s22s22p63s23p64s23d104p6 5s1
1s22s22p63s23p64s23d104p65s24d105p6 6s1
1s22s22p63s23p64s23d104p65s24d105p66s24f145d1056p6 7s1
Alkaline Earth Elements
1s2 2s2
1s22s22p6 3s2
1s22s22p63s23p6 4s2
1s22s22p63s23p64s23d104p6 5s2
1s22s22p63s23p64s23d104p65s24d105p6 6s2
1s22s22p63s23p64s23d104p65s24d105p66s24f145d1056
p6 7s2
Noble Gases
1s2
1s22s22p6
1s22s22p63s23p6
1s22s22p63s23p64s23d104p6
1s22s22p63s23p64s23d104p65s24d105p6
Valence electrons
• Electrons in outermost electron orbital
Halogens
Chalcogens
Blocks
S block - Filling available s orbitalsP block - Filling available p orbitalsD block – Filling 3d, 4d, 5d and 6d orbitalsF block – filling 4f and 5f orbitals
Trends in the Periodic Table
• Atomic radius
• Increases with
increasing number
of energy levels
Atomic Size
Ionization
• Energy ejects an
electron from atom’s
orbit
• Forms a CationX -> X+
Shielding Effect
Trends in Ionization Energy
Low Energy = Easier to remove electron
High Energy = Difficult to remove electron
Periodic Size Changes
Electronegativity
Electronegativity Trend
Electronegativity
• Ability to attractAn electron
Forms a AnionX -> X-
Ion Sizes
Ion Sizes
Periodic Trends
Boiling Point
Boiling Point Trends
Elemental Abundance
1. Hydrogen
2. Helium
3. Oxygen
4. Carbon
Rare earth elements
Alchemy
Nuclear Fusion
4 1H -----------> 4He
occurs in the core of stars
Fusion in SuperGiant Stars
• Betelgeuse is a red giant star in Orion
that is currently fusing Helium
and will become a supernova
3 4He ---------> 12C
Synthetic Elements
Lawrence’s Cyclotron
Superheavy Elements
• Transuranium Elements
– Produced by nuclear collisions
Island of Stability