Question

Which one of the following is an elemental substance: water, \(\mathrm{H}_{2} \mathrm{O} ;\) bronze, made by melting copper and tin together; table salt, \(\mathrm{NaCl}\); ozone, \(\mathrm{O}_{3} ;\) sulfur dioxide, \(\mathrm{SO}_{2} ?\)

Short answer

The elemental substance among the given options is ozone, \(\mathrm{O}_{3}\), as it is the only substance consisting of a single type of atom (oxygen).

Step-by-step solution

Define elemental substance

An elemental substance is a substance that consists of only one type of atom. To identify the elemental substance among the given options, we need to examine the composition of each substance and determine if it is made up of only one type of atom.

Analyze the composition of each substance

- Water, \(\mathrm{H}_{2}\mathrm{O}\), is made up of two hydrogen atoms (H) and one oxygen atom (O). - Bronze is a metallic alloy made by melting copper and tin together, so it contains at least two different types of atoms: copper (Cu) and tin (Sn). - Table salt, \(\mathrm{NaCl}\), consists of one sodium atom (Na) and one chlorine atom (Cl). - Ozone, \(\mathrm{O}_{3}\), is composed of three oxygen atoms (O). - Sulfur dioxide, \(\mathrm{SO}_{2}\), contains one sulfur atom (S) and two oxygen atoms (O).

Determine the elemental substance among the options

Among these substances, ozone, \(\mathrm{O}_{3}\), is the only substance that consists of a single type of atom (oxygen). All the other substances are made up of two or more different types of atoms.

State the answer

The elemental substance among the given options is ozone, \(\mathrm{O}_{3}\).

Key concepts

Composition of Substances

When we talk about the "composition of substances," we're exploring what substances are made up of. A substance's composition can tell us whether it's an elemental substance or a compound. Every substance consists of atoms, the basic building blocks of matter.
In a compound, like water (\(\mathrm{H}_{2}\mathrm{O}\)), these atoms are combined from different elements. Water is composed of hydrogen and oxygen atoms. This combination creates a substance that has different properties compared to its constituent elements. In contrast, a pure element contains only one type of atom. Understanding the composition helps in identifying whether a substance is elemental or a compound.

• A compound consists of atoms from different elements.
• An elemental substance consists of only one type of atom.
• The composition of a substance determines its classification.

Single Type of Atom

A single type of atom is a defining feature of elemental substances. An elemental substance is formed when there are atoms of only one chemical element present. For instance, ozone (\(\mathrm{O}_{3}\)) consists solely of oxygen atoms. This exclusive presence makes it an elemental substance.
When substances are composed of only one atom type, their properties are inherently different from substances with multiple atom types. For example, metals like gold (Au) and elements like hydrogen (H) exist as elemental substances because they contain only one kind of atom throughout.
This concept is crucial for understanding the purity and characteristics of substances.

• Elemental substances have one atom type.
• The purity of an elemental substance is linked to its single atom type.
• This singularity affects the properties and behavior of the elemental substance.

Chemical Elements

Chemical elements are pure substances consisting of one type of atom. They are found on the periodic table, representing the simplest form of matter that retains distinct chemical properties.
Elements include basic metals, nonmetals, noble gases, and more. Each element is unique and has a specific number of protons in its atomic structure, known as its atomic number. For example, oxygen is an element with an atomic number of 8, meaning it has eight protons.
Understanding chemical elements is key to discerning how different substances are formed and how they interact with each other in various chemical reactions and compounds.

• The periodic table is the chart of all known chemical elements.
• Elements are the building blocks of all matter.
• Each element's place on the periodic table provides information about its properties.