periodic families. the periodic table what does the word periodic mean? pe·ri·od·ic –adjective...
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Periodic Families
The Periodic Table
What does the word periodic mean? pe·ri·od·ic
–adjective 1. recurring at intervals of time: periodic revivals of an interest in handicrafts.
2. occurring or appearing at regular intervals: periodic visits of a mail steamer to an island.
3. repeated at irregular intervals; intermittent: periodic outbreaks of the disease. From Dictionary.com
Choose 1 definition and know it!
Mendeleev and the Periodic Table Dmitri Mendeleev
A Russian developed the first periodic table in 1869
He based his table upon the physical properties of the elements
He was even able to predict the properties of undiscovered elements
He made the table 40 years before the discovery of the electron
A gentle reminder
Columns on the Periodic Table They are called Groups or Families
Rows on the Periodic Table Periods
Groups and families include similar elements Metals are on the left of the zig-zag line Non-metals on the right of the zig-zag line
How are the elements arranged The elements are arranged by number of
protons, the atomic number The elements are not in mass number
Ar, number 18, has a larger mass than K, number 19
The same thing happens with Co and Ni
A new term
Valance electrons Electrons in the outermost shell
Remember electron configuration Usually the S and P sub –orbital How many valence electrons in Na, or Cl
S can hold 2 and P can hold 6 How many elements in period 2?
Coincidence… I think not.
Remember your “People” from outer Space What did you notice as you move down a
column? What you did you notice as you across a
row? The same thing happens in the periodic
table.
Group 1 Alkali MetalsKnow this group Metallic, soft Low melting point for a metal Highly reactive One valence electron
Group 2 Alkaline Earth MetalsKnow this group Higher melting points than alkali metals Soft and lightweight for a metal but harder that alkali
metals Low reactivity at room temperature 2 valence electrons Important compounds
Calcium oxide (lime) the 5th most produced chemical Calcium carbonate-chalk, marble, toothpaste abrasive and
antacid
Group 13 Boron Family
Metalloid Boron, Metal Al, Ga, In, Th Has 3 valance electrons Ions +3 Can be very hard (boron) Overall shiny, relatively soft and low melting point Can be excellent conductors (Al) Important compounds
Borax Aluminum oxide- used in sandpaper
Group 14 The Carbon Family
Non metal C, metalloid Si & Ge and metals tin and lead Has 4 valence electrons Density increases as you go down the group Hardness and melting point decrease as you go down the group Can form bonds with 4 other chemicals Important compounds
Methane CH4
Silicon dioxide- glass Buckminsterfullerene, nanotubes
Group 15 The Nitrogen Family Nonmetallic N, P; Metalloids arsenic, antimony (Sb)
and 1 metal bismuth 5 valence electrons, ion have a -3 charge Melting points increase then decrease Density increases steadily Important compounds
Ammonia NH3
Amino acids Bismuth subsalicylate
Group 16 Oxygen Family
Nonmetal O and S, metalloid Se and Te, lone metal polonium
6 valence electrons, has a charge of -2 Melting points increase Densities increase Important chemical
Water H2S the rotten egg smell, Hydrogen peroxide Sulfuric acid, the cheapest strong acid
Group 17 Halogen FamilyKnow this family Extremely reactive, F the strongest 7 valence electrons, charge of -1 Melting points increase but still well below 0 Densities increase Important compounds
HCl hydrochloric acid Bleach NaClO PCB
discontinued as a cancer risk Ammonium perchlorate
used in the shuttle
Group 18 Noble GasesKnow this family Eight valence electrons
Outer shell filled That is why He is in this group
Odorless colorless gases Unreactive
There are some exceptions
Reactivity in non metals
Reactivity in metals
Trends in reactivity
More reactive as you move down
More reactive as you move up
Atomic radius for metals increases
Atomic radius for non-metals decreases
Trends in atomic radius
Atomic radius decreases
• Least Metallic
• Most Reactive
V8
V2V4
• Positive ions
• Variable v-electrons
V6V5
V1
V2 V3 V7
Increasing reactivity
• Most reactive
• Most metallic
+1 +2 -2-3+/-4+3 0-1
Increasing reactivity
Unreactive gases
METALS
NON-METALS
METALLOIDS
V8
V2V4 V6V5
V1
V2 V3 V7