Transcript Slide 1 - Teacher Pages

Props.
in a group are similar because
the atoms have the same # of
electrons in their outer energy levels
Atoms will take, give or share
electrons with each other in order to
have a complete set of electrons
Elements that undergo this process
are called reactive
Contains metals
1 electron in the outer level
Soft enough to cut with a knife
Silver color, shiny, low density
Very reactive, react with water to form hydrogen gas
Most reactive metals because they can easily give away
the one outer shell electron
 So reactive that in nature they are found only combined
with other elements
 Cmpds. formed from them are very useful
 Ex.-Sodium Cholride-Table salt, Potassium BromideUsed in photography
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2 electrons in outer level
Very reactive, but less reactive than
alkali metals
More difficult for atoms to give 2
electrons than 1 when joining with other
atoms
Other properties: Silver color, higher
densities than alkali metals
 1 or 2 electrons in the outer level
 Less reactive than alkaline-earth metals
 Other properties: Shininess, good conductors of
thermal energy and electric current, higher
densities and MP than elements in Groups 1 and 2
(except mercury-liquid @ room temp.)
 Many are silver-not all-Gold is an example
 Some are reactive and some are not that reactive
 Lanthanides & Actinides:placed below the table so
the table is not so wide
 Lanthanides:shiny, reactive metals.
 Actinides:radioactive(unstable)
 Elements after 94 are made in labs
• This group contains one metalloid and four
metals
• 3 electrons in the outer level
• They are reactive
• They are solid at room temp.
• Most common element is Aluminum-most
metal found in the Earth’s crust
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Contains 1 nonmetal, 2 metalloids and 2 metals
4 electrons in the outer level
The reactivity varies among the elements
Solid at room temperature
Example of a nonmetal in the Carbon group:
Diamonds: hardest material known. Soot:
formed from burning oil, coal and wood.
Both are natural forms of Carbon
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Contains 2 nonmetals, 2 metalloids and 1 metal
5 electrons in the outer level
Reactivity varies among the elements
Solid at room temp. except for nitrogen (it is
a gas) 80% of the air you breathe
Nitrogen-not very reactive but Phosphorous is
extremely reactive (striking a match)
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Contains 3 nonmetals, 1 metalloid, and 1 metal
6 electrons in the outer level
These elements are reactive
All but oxygen are solid at room temp.
Oxygen makes up about 20% of the air you
breathe.
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Contains nonmetals
7 electrons in the outer level
Very reactive because their atoms only need
to gain only 1 electron to have a complete
outer level
Poor conductors of electric current, violent
reactions with alkali metals to form salts,
never in uncombined forms in nature
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Contains nonmetals
8 electrons in the outer level (except helium
which has 2)
Unreactive elements-full set of electrons in
their outer level
Colorless, odorless gases at room temp.
These are useful gases-argon: lightbulbs,
helium: makes blimps and weather balloons
float
 1 electron in the outer level
 Hydrogen is reactive
 Properties of H do not match any other group so it is set
apart.
 Colorless, odorless gas at room temp., low density, explosive
reaction with oxygen
 Can give away one electron when they join with other atoms.
 Physical props. of hydrogen are more like nonmetals than
metals.
 Hydrogen is found in stars. Most abundant element in the
universe.
 Useful in rocket fuel because it is so reactive