Physical Science Ch 5 Periodic Table. Standards Relate properties of atoms and their position in the...
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Transcript of Physical Science Ch 5 Periodic Table. Standards Relate properties of atoms and their position in the...
Physical Science
Ch 5 Periodic Table
Standards• Relate properties of atoms and their position in the
periodic table to the arrangement of their electrons.• Differentiate among conductors, semiconductors, and
insulators.• Describe how scientific inferences are drawn from
scientific observations & provide examples.• Discuss effects of technology on environmental quality.• Predict human impact on environmental systems .• Weigh alternative strategies for solving specific societal
problems by comparing human, economic, and environmental aspects.
Chapter assignments from the book:
• 139/26-28
• 140/1-8
• 150/107
• 155/1-8
• 164/1-4
Mendeleev
1. Placed elements in order by mass2. Elements with similar properties were in
the same column3. His periodic table could be used to
predict properties of newly discovered elements
4. He predicted an unknown element would have properties similar to aluminum and called it eka-aluminum
• The Periodic Table of the Elements is a way to arrange the elements to show a large amount of information and organization.
• The Periodic Table is NOW arranged in order of increasing atomic number.
Periodic Table Organization
1. As you read across the chart from right to left, a row of elements is a Period.
2. As you read down the chart from top to bottom, a column of elements is a Group or Family
3. Elements in a column have similar properties
Group IA alkali metals
Group IIAalkaline earth Metals
Group IIIB-IIBtransition metals
Inner Transition Metals
Lanthanide Series - also called the rare earth elements.
Actinide Series
Group VIIIA noble gases
or inert gases
Group VIIA - halogens
Bright Green - nonmetals
Purple - metalloids or
semiconductors
Light Blue - other metals
In the periodic table
• A set of properties repeats from row to row
• The atomic number increases from left to right
• The atomic number is the number of protons in an atom of an element
• The atomic number is equal to the number of electrons when an atom is neutral
http://periodic.lanl.gov/default.htm
• Periodic Table of the elements
• Los Alamos
• Atomic Mass - the mass of one mole of an atom. (One mole is 6.02 x 1023 atoms)
• Mass Number (the atomic mass number rounded) - the total amount of protons and neutrons in the nucleus of an atom
• Example: Tantalum, atomic # 73• 180.948 is the atomic mass• 181 is the p+n total• Subtract 73 p and it has 108 neutrons• Now you try with Zinc• 65.39 65P+N - 30P = 35N
Electrons
• Are found in energy levels (or orbitals) around the nucleus.
• The period an element is in indicates how many energy levels in which an atom has electrons (see long periodic chart given to you)
• Ca has 2 8 8 2
• Al has 2 8 3
Energy Level # of orbitals Max # of e’s
1 1 (En. Lev.
Squared) S2 (2 x # of orbitals)
2 4 P 8
3 9 D 18
4 16 F 32
Atomic Mass
• The weighted average of the masses of an element’s isotopes found in nature.
• Atomic mass unit - one twelfth of the mass of a carbon -12 atom (Carbon – 12 is the Standard Mass)
• The unit is an amu (1/12 of the mass of C-12.)
Reactivity Patterns
• Reactivity is closely related to the number of VALENCE electrons in the atoms of an element.– Most reactive metal group is IA with 1 valence e– Most reactive nonmetal group is VIIA with 7 valence
e’s
• On the metal side of the Periodic Chart, going down a group, the elements get more reactive. Cs > Na (This is determined by how they behave when placed in water)
• On the nonmetal side, going up, the elements get more reactive. F > At
• Reactive metals EASILY lose valence electrons (1 or 2 to have 8 in outer E level)
• Reactive nonmentals EASILY take valence electrons (to have 8 in outer E level.
Most Reactive
Metals
Most reactive
NonMetalsHighly reactive elements are stored in containers containing oils or argon
More on Reactivity
• Examples:
• Ge would be a better electrical conductor that Se (Ge more metallic than Se)
• Two highly reactive elements in Period 3 are the metal Na and the nonmetal Cl
Most metals are…
• Good conductors of heat and electricity
• Malleable
• Ductile
Most nonmetals are…
• Poor conductors of heat and electricity
• Brittle
Etc.
• Some highly reactive metals are stored in argon
• Sodium is found in nature only in compounds (highly reactive)
• Carbon is found in most compounds in your body except water