Download 5.2 The Modern Periodic Table

5.2: The
Modern
Periodic Table
Arrangement of the Periodic Table
• Elements are arranged by increasing
atomic number (number of protons &
electrons).
• Each row in the table of elements is a
period. (Period # = # of energy levels)
• Each column in the periodic table is
called a group. (Group # = # of valence
electrons)
– similar electron configurations
– similar chemical properties
Classes of Elements
• Three different ways to classify elements:
• State of Matter (Look @ the color the element’s symbol is written in)
• solid—black symbol
• liquid—purple symbol
• gas—red symbol
• Occurrence in nature
• elements that do not occur naturally—white symbol.
• General properties
• metal—blue background
• nonmetal—yellow background
• metalloid—green background
Metals
• majority of the elements on the
periodic table
• good conductors of electric
current and heat
• Except for mercury, metals are solids at room
temperature.
• Most metals are malleable.
• Many metals are ductile; that is, they can be
drawn into thin wires.
Transition Metals
• metals in groups 3 through
12
• form a bridge between the
elements on the left and
right sides of the table
Nonmetals
• generally have properties
opposite to those of metals
• are poor conductors of heat and electric
current.
• Nonmetals have low boiling points–many
nonmetals are gases at room temperature.
• Nonmetals that are solids at room
temperature tend to be brittle.
Metalloids
• Located between metals and nonmetals
• properties that fall between those of
metals and nonmetals
– a metalloid’s ability to conduct electric current
varies with temperature
• Ex: Silicon (Si) and germanium (Ge) are good
insulators at low temperatures and good
conductors at high temperatures.
Questions…(Answer on your notes)
1. What are the three categories we use to
classify elements on the periodic table?
2. What is a row of the periodic table called?
3. What is a column called?
4. What is the group name for elements in
groups 3 through 12?
5. What are the differences between metals
and nonmetals?