What Are the Properties of Nonmetals?

A nitrogen tank controlled by a scientist.
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A nonmetal is simply an element that does not display the properties of a metal. It is not defined by what it is, but by what it is not. It doesn't look metallic, can't be made into a wire, pounded into shape or bent, doesn't conduct heat or electricity well, and doesn't have a high melting or boiling point.

The nonmetals are in the minority on the periodic table, mostly located on the right-hand side of the periodic table. The exception is hydrogen, which behaves as a nonmetal at room temperature and pressure and is found on the upper left corner of the periodic table. Under conditions of high pressure, hydrogen is predicted to behave as an alkali metal.

Key Takeaways: The Nonmetals

  • The nonmetals are a small group of elements on the periodic table.
  • These elements are located on the righthand side of the table, with the exception of hydrogen.
  • The nonmetals include the group called the nonmetals, as well as the halogens and the noble gases.
  • Nonmetals typically don't look metallic. Often, they are colorful.
  • Most nonmetals take many forms called allotropes. For example, diamond and graphite are both pure carbon.
  • Nonmetals are typically poor conductors of heat and electricity, with low melting and boiling points. They tend not to be malleable or ductile, so they form brittle solids.
  • Nonmetals include solids, liquids, and gases at room temperature and pressure.

Nonmetals on the Periodic Table

The nonmetals are located on the upper right side of the periodic table. Nonmetals are separated from metals by a line that cuts diagonally through the region of the periodic table containing elements with partially filled p orbitals. The halogens and noble gases are nonmetals, but the nonmetal element group usually consists of the following elements:

  • hydrogen
  • carbon
  • nitrogen
  • oxygen
  • phosphorus
  • sulfur
  • selenium

The halogen elements are:

  • fluorine
  • chlorine
  • bromine
  • iodine
  • astatine
  • tennessine (possibly, although most scientists think this element will behave as a metalloid)

The noble gas elements are:

  • helium
  • neon
  • argon
  • krypton
  • xenon
  • radon
  • oganesson - This element is predicted to be a liquid noble "gas", but is still a nonmetal.

Properties of Nonmetals

Nonmetals have high ionization energies and electronegativities. They are generally poor conductors of heat and electricity. Solid nonmetals are generally brittle, with little or no metallic luster. Most nonmetals have the ability to gain electrons easily. Nonmetals display a wide range of chemical properties and reactivities.

Summary of Common Properties

Here is a summary of the properties of the nonmetals.

  • High ionization energies
  • High electronegativities
  • Poor thermal conductors
  • Poor electrical conductors
  • Brittle solids—not malleable or ductile
  • Little or no metallic luster
  • Gain electrons easily
  • Dull, not metallic-shiny, although they may be colorful
  • Lower melting points and boiling point than the metals

Comparing the Metals and Nonmetals

The chart below displays a comparison of the physical and chemical properties of the metals and nonmetals. These properties apply to the metals in general (alkali metals, alkaline earth, transition metals, basic metals, lanthanides, actinides) and nonmetals in general (nonmetals, halogens, noble gases).

Metals Nonmetals
chemical properties easily lose valence electrons easily share or gain valence electrons
1-3 electrons (usually) in the outer shell 4-8 electrons in the outer shell (7 for halogens and 8 for noble gases)
form basic oxides form acidic oxides
good reducing agents good oxidizing agents
have low electronegativity have higher electronegativity
physical properties solid at room temperature (except mercury) may be liquid, solid, or gas (noble gases are gases)
have metallic luster do not have metallic luster
good conductor of heat and electricity poor conductor of heat and electricity
typically malleable and ductile usually brittle
opaque in a thin sheet transparent in a thin sheet

Sources

  • Atkins, P. A. (2001). The Periodic Kingdom: A Journey Into the Land of the Chemical Elements. London: Phoenix. ISBN 978-1-85799-449-0.
  • Brady, J. E.; Senese, F. (2009). Chemistry: The Study of Matter and its Changes (5th ed.). New York: John Wiley & Sons. ISBN 978-0-470-57642-7.
  • Challoner, J. (2014). The Elements: The New Guide to the Building Blocks of our Universe. Carlton Publishing Group. ISBN 978-0-233-00436-5.
  • Oxtoby, D. W.; Gillis, H. P.; Butler, L. J. (2015). Principles of Modern Chemistry (8th ed.). Boston: Cengage Learning. ISBN 978-1-305-07911-3.
  • Steudel, R. (1977). Chemistry of the Non-metals: With an Introduction to Atomic Structure and Chemical Bonding. Berlin: Walter de Gruyter. ISBN 978-3-11-004882-7.
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Helmenstine, Anne Marie, Ph.D. "What Are the Properties of Nonmetals?" ThoughtCo, Sep. 2, 2022, thoughtco.com/nonmetals-definition-and-properties-606659. Helmenstine, Anne Marie, Ph.D. (2022, September 2). What Are the Properties of Nonmetals? Retrieved from https://www.thoughtco.com/nonmetals-definition-and-properties-606659 Helmenstine, Anne Marie, Ph.D. "What Are the Properties of Nonmetals?" ThoughtCo. https://www.thoughtco.com/nonmetals-definition-and-properties-606659 (accessed September 29, 2022).