CHAPTER 5: THE PERIODIC TABLESection 3: Families of Elements

OBJECTIVESWhat does each element family have in

common?

What are the families of metals?

What are some of the families of nonmetals?

What are semiconductors?

CLASSIFYING ELEMENTS FURTHERWhat does each element family have in

common?

In general, the elements in a family have the same number of valence electrons.

METALSWhat are the families of metals?Families of metals include the alkali metals,

the alkaline-earth metals, and the transition metals.alkali metal: one of the elements of Group 1 of the

periodic table

alkaline-earth metal: one of the elements of Group 2 of the periodic table

transition metal: one of the metals that can use the inner shell before using the outer shell to bond

METALS, CONTINUEDThe alkali metals

are very reactive.Alkali metals are in

Group 1, on the left edge of the periodic table.

They are reactive because they have one valence electron that is easily removed.

They are soft and shiny, and many have similar melting points, boiling points, and densities.

METALS, CONTINUEDAlkaline-earth metals

form compounds that are found in limestone and in the human body.Alkaline-earth metals are in

Group 2.

Alkaline-earth metals are less reactive than alkali metals, but still react to form positive ions.

In general, alkaline-earth metals are harder, denser, stronger, and have higher melting points than alkali metals.

METALS, CONTINUEDTransition metals are in the middle of the

periodic table.With the exception of mercury, transition metals are harder,

more dense, and have higher melting points than alkali metals and alkaline-earth metals.

They are also less reactive, but they can form positive ions.

NONMETALSWhat are some of the families of

nonmetals?Families of nonmetals include the noble

gases and the halogens.

noble gas: one of the elements of Group 18 of the periodic table

halogen: one of the elements of Group 17 of the periodic table

NONMETALS, CONTINUEDThe noble gases

are relatively inert.The noble gases are in

Group 18.

They exist as single atoms instead of as molecules.

They are inert, or unreactive, because their s and p orbitals are filled. In general, they do not form ions or compounds.

NONMETALS, CONTINUEDThe halogens

combine easily with metals to form salts.The halogens are in

Group 17.

With the addition of a single electron, halogens become stable.

They combine easily with metals (especially alkali metals) to form salts.

NONMETALS, CONTINUEDNonmetals and their

compounds are plentiful on Earth.

Six other nonmetals are on the right side of the periodic table.

Carbon can form many compounds.

There are millions of carbon-containing compounds.

SEMICONDUCTORSWhat are

semiconductors?As their name

suggests, semiconductors are able to conduct heat and electricity under certain conditions.

Semiconductors are also called metalloids.