6.1. History of the Periodic Table http://www.ck12.org
Ametalloidis an element with properties that are intermediate between those of metals and nonmetals. Silicon is a
typical metalloid (Figure6.7). It has luster like a metal but is brittle like a nonmetal. Silicon is used extensively in
computer chips and other electronics because its electrical conductivity is in between that of a metal and a nonmetal.
Metalloids can also be called semimetals. On the periodic table above, the elements that are shaded orange are
considered to be metalloids, and they include most of the elements that border the stair-step line. Notice that
aluminum also borders the line, but it is considered to be a metal because its properties closely resemble those of
metals.
FIGURE 6.7
Silicon is an example of a metalloid be-
cause it has some properties that are
characteristic of a metal and some that
are characteristic of a nonmetal.Explore some interactive periodic tables at:
- Periodic Table: http://chemistry.about.com/library/blperiodictable.htm?nl=1
- It’s Elemental (NOVA): http://www.pbs.org/wgbh/nova/physics/periodic-table.html
- It’s Elemental! Jefferson Lab: http://education.jlab.org/itselemental/index.html
Watch this Khan Academy video on Groups of the Periodic Table (11:51):
MEDIA
Click image to the left for more content.Lesson Summary
- Mendeleev arranged chemical elements into a periodic table by arranging them in order of increasing atomic
mass. - According to the periodic law, the physical and chemical properties of the elements are periodic functions of
their atomic numbers.