Video Transcript
The physical properties of boron
suggest that it could be classified as a metal and a nonmetal. What name is given to elements that
exhibit properties of both metals and nonmetals? (A) Alloys, (B) hybrids, (C)
metalloids, (D) inert gases, (E) lanthanides.
The 118 known elements are all
unique. But many of the elements have
similar physical properties, allowing them to be grouped into broad categories. One of these broad categories is
metals. The metals are solid at room
temperature, except for the metal mercury, which is a liquid.
When clean and polished, metals are
shiny or lustrous. Metals are malleable and
ductile. “Malleable” means capable of being
extended or shaped by beating with a hammer or by the pressure of rollers. So, most metals can be hammered
into flat sheets or rolled into flat sheets. “Ductile” means capable of being
drawn or pulled into a wire or thread. Metals like copper can be drawn
into a wire.
Metals are also good thermal and
electrical conductors. So, metals are good at transferring
electricity and thermal energy, which we feel as heat. This is why metals are used to make
pots and electrical wires.
Some of the elements are
categorized as nonmetals. At room temperature, most of the
nonmetals are solids, some are gases, and only one nonmetal, bromine, is a
liquid. Nonmetals tend to have a dull
appearance. Unlike metals, nonmetals are
brittle. This means that when a nonmetal is
hammered, it breaks or shatters. Most nonmetals are poor thermal and
electrical conductors. So they do not conduct heat or
electricity well. One exception to this is graphite,
one of the forms of the element carbon, which is a good thermal and electrical
conductor.
Some elements like boron exhibit
properties of both metals and nonmetals. These elements are classified as
metalloids. Metalloids are solid at room
temperature. They are lustrous like metals but
brittle like nonmetals. Metalloids are intermediate thermal
and electrical conductors, or semiconductors.
In conclusion, the name that is
given to elements that exhibit properties of both metals and nonmetals is
metalloids, answer choice (C).
