the periodic table families. why is it important to me? useful because it allows you to determine...
TRANSCRIPT
The Periodic Table Families
Why is it important to me?
• Useful because it allows you to determine properties of elements by their location on the table.
Dmitri Mendeleev: Father of the Table
HOW HIS WORKED…• Put elements in rows by
increasing atomic mass.• Put elements in columns
by the way they reacted.
SOME PROBLEMS…• Left blank spaces for
undiscovered elements.
The Current Periodic Table
• Now the elements are put in rows by increasing
ATOMIC NUMBER (number of protons)!!
Reactivity
• Elements are in numbered groups, or families.• Most reactive groups are #1 (alkali metals) and
#17 (halogens). • As you move towards the middle of the table,
elements become less reactive.• Group #18 does not react at all (noble gases).
- Atoms, Bonding, and the Periodic Table
Valence Electrons and Bonding• Elements in the same family have similar
properties because of their valence electrons.• Number determines available electrons for
bonding; max is 8.• The less valence electrons an atom needs to be
close to 8, the more reactive it is.
Electron Dot Diagrams
• Draw the symbol• Determine the # of V.E.• Draw that many dots around symbol
Metals• 1-4 valence electrons.• Gives away electrons in a reaction.• Physical properties include:
– Luster (shiny)– Conducts heat and electricity – High densities– High melting points– Ductile (stretched into thin wires)– Malleable (hammered into thin sheets)
Nonmetals• 5-8 valence electrons.• Gains electrons in reactions.• Physical Properties:
– No luster– Poor conductors of heat and electricity– Brittle (break easily)– Not ductile or malleable– Lower densities and melting points
Metalloids
• Properties of both metals and nonmetals.• Along the stair step• Shiny or dull.• Conduct heat and electricity okay.• Ductile and malleable.
Hydrogen
• Hydrogen is a reactive gas.• In its own family because its
properties are so different.
Alkali Metals
• 1 Valence Electron• Very reactive; always
combined with something else in nature (like in salt).
Alkaline Earth Metals
• 2 Valence Electrons• Reactive; usually
combined with something else.
Transition Metals
• 1-4 valence electrons (no pattern).
• Less reactive, harder metals
Boron Family
• 3 Valence Electrons• Less reactive
Carbon Family • 4 Valence Electrons• Not very reactive – would
rather share electrons.
Nitrogen Family• 5 Valence electrons.• More reactive than
carbon (not much).
Oxygen Family
• 6 Valence electrons.• Reactive; usually
combined with a metal.
Halogens
• 7 Valence electrons• Very reactive, volatile
nonmetals• Always combined with
another element in nature.
The Noble Gases
• 8 Valence electrons (full).• Don’t normally react with
other elements.