Chapter 12
The Periodic Table
Section 2 – Grouping the
Elements
Essential Questions
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Why do elements in a group have similar
characteristics? (12-2)
What are the properties of the elements in
each group of the periodic table? (12-2)
Grouping the Elements
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Properties of a group of elements are
similar
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Atoms have the same number of electrons in
the outer energy level
Group 1: Alkali Metals
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Group contains: metals
Electrons in outer level: 1
Reactivity: very reactive
Other shared properties: softness, color
of silver, shininess, low density
Used for: flavoring food (sodium chloride
- table salt), photography (potassium
bromide)
Group 2: Alkaline-Earth Metals
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Group contains: metals
Electrons in outer level: 2
Reactivity: very reactive, but less than
group 1
Other shared properties: color of silver,
higher density than alkaline metals
Used for: airplane-making compounds,
cement, chalk
Groups 3-12: Transition Metals
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Group contains: metals
Electrons in out level: 1 or 2
Reactivity: less reactive than alkalineearth metals
Other shared properties: shininess, good
conductors of thermal and electric energy;
higher densities and melting points
Lanthanides and Actinides
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Lanthanides are Period 6 transition metals
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Shiny, reactive
Used to make steel
Actinides are Period 7 transition metals
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All are radioactive
All are man-made in laboratories
Group 13: Boron Group
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Group contains: 1 metalloid & 5 metals
Electrons in out level: 3
Reactivity: reactive
Other shared properties: solids at room
temperature
Used for: auto parts, aluminum foil, cans,
siding
Group 14: Carbon Group
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Group contains: 1 nonmetal; 2 metalloids;
3 metals
Electrons in out level: 4
Reactivity: varies among elements
Other shared properties: solids at room
temperature
Used for: compounds necessary for life
(proteins, fats, carbohydrates), tin
Group 15: Nitrogen Group
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Group contains: 2 nonmetals, 2
metalloids, 2 metals
Electrons in out level: 5
Reactivity: varies among the elements
Other shared properties: solids at room
temperature (except for nitrogen)
Used for: nitrogen is about 80% of air
you breathe, also used for fertilizer
Group 16: Oxygen Group
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Group contains: 3 nonmetals; 1 metalloid;
1 metal
Electrons in out level: 6
Reactivity: reactive
Other shared properties: solids at room
temperature, except oxygen
Used for: oxygen is 20% of air you
breathe; sulfur is used in industry
Group 17: Halogens
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Group contains: nonmetals
Electrons in out level: 7
Reactivity: very reactive
Other shared properties: poor conductors
of electricity; violent reactions with alkali
metals
Used for: readily combine with other
atoms to form salts, and cleaning agents
Group 18: Noble Gases
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Group contains: nonmetals
Electrons in out level: 8 (except helium,
which has 2)
Reactivity: unreactive
Other shared properties: colorless,
odorless gases at room temperature
Used for: (very useful) lights, floatation
Hydrogen
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Group contains: ONLY Hydrogen
Electrons in out level: 1
Reactivity: reactive
Other properties: colorless, odorless gas
at room temperature, low density,
explosive reaction w/ oxygen
Used for: fuel in rockets; most abundant
element in universe