Short answer
Metals are elements that typically combine good electrical and thermal conductivity with metallic luster and the ability to deform without breaking. Metalloids are elements classified as having a mixture of metallic and nonmetallic properties. Silicon, for example, can look metallic while having very different electrical behavior from an ordinary metallic conductor. 1 2 3
Here, metal means a category of chemical elements. Everyday descriptions also call alloys such as steel “metal,” but that broader material use is a different question. This article follows the introductory chemistry convention used by OpenStax, which lists boron, silicon, germanium, arsenic, antimony, and tellurium as metalloids. 2
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At a glance
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| Question | Metal | Metalloid |
|---|---|---|
| What is being classified here? | A chemical element. | A chemical element. |
| Typical appearance | Often lustrous when a clean surface is exposed. | Several are metallic-looking too. |
| Typical electrical behavior | Good conduction is a characteristic property. | Depends on the element and conditions; silicon is a semiconductor. |
| Mechanical behavior | Many can be bent, rolled, or drawn into wire. | Metallic appearance does not imply that workability. |
| Periodic-table pattern | Most lie toward the left and center. | The usual examples lie near the metal/nonmetal boundary. |
| Is one visual test sufficient? | No. | No. |
Sources: introductory classification 1 2; silicon’s behavior 3. These are patterns, not a complete specification for every element or sample.
What each thing is
Metal
In this classification, a metal is an element whose characteristic properties fit the metallic group. Familiar examples include iron, copper, and aluminum. Conductivity, luster, malleability, and ductility are useful patterns: malleable materials can be shaped under compression, while ductile materials can be drawn into wire. 1
The category groups related behavior. It does not mean every metal has the same hardness, reactivity, melting point, or suitability for a particular object.
Metalloid
A metalloid is an element placed between the broad metallic and nonmetallic groups because its properties do not fit either simple stereotype. The six-element convention used here is a chemistry teaching classification. It should not be read as one shared atomic structure or one identical set of engineering properties. 1 2
For example, silicon and germanium have diamond-like crystal structures, while arsenic and antimony have different, layered structures. A common category name does not erase these differences. 2
Key differences
A metallic appearance is not the same as metallic electrical behavior. Silicon can be shiny and gray, yet its semiconductor behavior differs from that of a good metallic conductor. Its electrical response is central to its use in electronics. 3
Composition and conditions matter to conductivity. Adding carefully controlled impurities to silicon changes its electrical behavior. Temperature matters as well. Consequently, “conducts electricity” versus “does not conduct electricity” is too crude a test for this distinction. 3
The periodic table shows a pattern, not an identification procedure. Once an element is known, a chemistry reference can show how it is classified. Looking at an unidentified shiny fragment cannot establish its element or category. The classification rests on a collection of chemical and physical properties. 1 2
How to tell them apart
For a named element, consult a periodic table with an explicit classification key and read the element’s properties. For an unknown sample, first establish what material it is through documentation or appropriate analysis; then ask how that element is categorized.
A photograph cannot establish conductivity, crystal structure, or chemical identity. Even an electrical measurement describes that sample under the measurement conditions. Silicon’s response to impurities illustrates why such a measurement is not a complete category test. 3
Where they overlap
Metals and metalloids are both categories applied to elements. Their observable properties overlap: a metalloid can look metallic, and elements in both groups can conduct electricity to some degree. The category is a summary of behavior, rather than a claim that every characteristic falls on the same side of a dividing line. 1 2
Edge cases
Doped silicon remains silicon-based material. Changing its conductivity with small additions does not mean that a piece has simply become an ordinary metal in the periodic-table sense. Its composition and electronic behavior need separate descriptions. 3
Silicon dioxide is a compound, not a sample of elemental silicon. Quartz and many glass materials contain silicon chemically combined with oxygen. They should not inherit the elemental classification merely because their names or ingredients include silicon. 2 3
“Metalloid” is not a universal performance specification. Arsenic, silicon, and tellurium differ in their structures and chemistry. Consult the element-specific properties when the practical behavior matters. 2
Why the distinction exists
The periodic table organizes recurring patterns in elemental properties. A metal/nonmetal split captures a broad trend, but some elements show a combination of behaviors. The metalloid category gives introductory chemistry a useful way to discuss that boundary without treating all intermediate elements as identical. 1 2
Common misconceptions
- “Anything shiny is a metal.” Silicon can also have a metallic-looking surface. 3
- “Metalloids are mixtures of metals and nonmetals.” The term here classifies individual elements. 2
- “Every metalloid behaves like silicon.” Their structures and chemistry vary. 2
- “A silicon-containing object is elemental silicon.” Silicon compounds are distinct substances. 2
Examples
Copper is a metal in the periodic-table classification. Silicon is a metalloid in the convention used here. Quartz, SiO₂, is a compound containing silicon; classifying the silicon element does not describe the whole compound’s behavior. These examples distinguish elemental identity from a material’s ingredients. 1 2 3
Sources
Sources checked October 3, 2026.
- OpenStax, Chemistry 2e — The Periodic Table. Element classification and property patterns.
- OpenStax, Chemistry 2e — Structure and General Properties of the Metalloids. The six-element convention, structures, and compounds.
- Royal Society of Chemistry — Silicon. Element identity, appearance, and semiconductor behavior.