1. Metals
* Physical Properties:
* Shiny: Most metals have a lustrous, reflective surface.
* Malleable: They can be hammered into thin sheets.
* Ductile: They can be drawn into wires.
* Good Conductors: They conduct heat and electricity well.
* Solid at Room Temperature: (Except for mercury, which is liquid)
* High Density: Metals are generally dense.
* Chemical Properties:
* Form Cations: They tend to lose electrons and form positively charged ions (cations).
* Reactive: Some metals are highly reactive (like sodium and potassium), while others are less reactive (like gold and platinum).
2. Nonmetals
* Physical Properties:
* Dull: Nonmetals lack a shiny appearance.
* Brittle: They tend to break easily.
* Poor Conductors: They are poor conductors of heat and electricity (except for carbon in the form of graphite).
* Gases at Room Temperature: Many nonmetals are gases at room temperature (oxygen, nitrogen, chlorine).
* Low Density: Nonmetals are generally less dense than metals.
* Chemical Properties:
* Form Anions: They tend to gain electrons and form negatively charged ions (anions).
* Varied Reactivity: Nonmetals exhibit a wide range of reactivity.
3. Metalloids (Semimetals)
* Properties: Metalloids have properties that fall somewhere between metals and nonmetals.
* Semiconductors: They conduct electricity better than nonmetals but not as well as metals. Their conductivity can be controlled, making them valuable in electronics.
* Brittle: Metalloids are generally brittle.
* Shiny or Dull: Their appearance can vary.
* Solid at Room Temperature: Metalloids are solid at room temperature.
Examples:
* Metals: Iron (Fe), copper (Cu), gold (Au), aluminum (Al), silver (Ag)
* Nonmetals: Oxygen (O), nitrogen (N), chlorine (Cl), sulfur (S), phosphorus (P), bromine (Br)
* Metalloids: Silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te)
Key Point: While these properties are helpful for identifying metals, nonmetals, and metalloids, there are exceptions to every rule. Always refer to a periodic table for confirmation.
