Question Video: Identifying the List of Physical Properties Used to Classify Elements as Metals, Nonmetals, and Metalloids | Nagwa Question Video: Identifying the List of Physical Properties Used to Classify Elements as Metals, Nonmetals, and Metalloids | Nagwa

# Question Video: Identifying the List of Physical Properties Used to Classify Elements as Metals, Nonmetals, and Metalloids Science • First Year of Preparatory School

What are the physical properties used to classify elements into metals, nonmetals, or metalloids?

05:35

### Video Transcript

What are the physical properties used to classify elements into metals, nonmetals, or metalloids? (A) Reactivity, density, and mass. (B) Physical state, hardness, and color. (C) Ability to burn, corrosivity, and texture. (D) Luster, mass, and conductivity. (E) Luster, conductivity, and malleability.

In this question, we need to identify which of the answer choices is a list of physical properties that are used to classify the elements on the periodic table as metals, nonmetals, or metalloids. Let’s first discuss what a physical property is.

A physical property is a property of a substance that can be observed without changing the composition of the substance. For example, if we placed a piece of solid carbon on a balance, we could measure its mass. Mass is a property that depends on how much of a substance we have. So, if we had the same amount of another substance and placed it on the balance, it would have the same mass. We can see that mass is listed as a property in answer choice (D). Samples of any two elements could have the same mass, so mass cannot be a property used to classify elements as metals, nonmetals, or metalloids. Mass is also listed in answer choice (A), but let’s come back to that later. For now, let’s eliminate answer choice (D).

When we observe a physical property, such as mass, color, or density, we do not change what a substance is made of. Before measuring the mass of the carbon, it was composed of only carbon atoms. After making the measurement, it was still composed of only carbon atoms. Now, let’s say we wanted to find out if carbon can be burned. We could try to ignite the piece of carbon. In doing so, a chemical reaction would take place. The carbon would react with oxygen in the air to form carbon dioxide. The result of observing carbon’s ability to burn is that carbon is converted into a new substance, carbon dioxide gas, which has a completely different composition.

Instead of being made of only carbon atoms, carbon dioxide molecules are composed of both carbon and oxygen. When we burn carbon, we are observing a chemical property. A chemical property is a property of a substance that can only be observed by changing the composition of the substance. Let’s take a look at answer choice (C). We see “ability to burn” in the list of properties. Since we now know that this is a chemical property, not a physical property, we can eliminate answer choice (C).

Now let’s come back to answer choice (A). Density and mass are physical properties. But we already know that mass cannot be used to classify elements as metals, nonmetals, or metalloids. We also know that when a chemical reaction takes place, a chemical property is being observed. So, if we observe how reactive an element is, we are observing a chemical property, not a physical property. For all of these reasons, we can eliminate answer choice (A).

The remaining answer choices only contain physical properties. So, now we need to determine which of these are the physical properties used to classify elements as metals, nonmetals, or metalloids. Most of the 118 known elements are metals. Less are nonmetals. And even less are metalloids. A metalloid is an element that has the properties of both metals and nonmetals. Most metals are solids at room temperature. All metalloids are solids at room temperature. And nonmetals may be solids, liquids, or gases at room temperature. Physical state is listed in answer choice (B). But if most metals, some nonmetals, and all metalloids are solids at room temperature, then physical state cannot be used to classify an element as a metal, nonmetal, or metalloid. So, we can eliminate answer choice (B).

This leaves only answer choice (E), which must be the correct answer. There are important differences in the conductivity of the elements. Metals tend to be very conductive. Metalloids are less conductive. And nonmetals tend to be the least conductive. So, conductivity is a physical property that can be used to classify an element as a metal, nonmetal, or metalloid. Malleability is another property that is used to classify the elements. An element is malleable if it can be shaped by being struck with a hammer or if pressure is applied. In general, metals are malleable. However, metalloids and nonmetals tend to not be malleable. Finally, most metals are lustrous, or shiny. But most metalloids and nonmetals are not lustrous.

In conclusion, the physical properties that are used to classify elements into metals, nonmetals, or metalloids are luster, conductivity, and malleability, or answer choice (E).

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