Question

A pure sample of a(n) ___ contains only one kind of atom.

Short answer

A pure sample of a(n) $\underset{―}{element}$ contains only one kind of atom.

Step-by-step solution

Fill in the blank

The term we are looking for is "element." An element is a pure chemical substance consisting of a single type of atom. A pure sample of a(n) $\underset{―}{element}$ contains only one kind of atom.

Key concepts

Pure Sample

In chemistry, the term "pure sample" refers to a material that contains only one type of substance without any contamination or mixture of other substances. This purity ensures that all properties observed are attributable solely to the substance of interest. With a pure sample, we can accurately study its characteristics without interference from other variables.
Pure samples are crucial in scientific experiments. They ensure accurate and reliable results. If an impurity is present, it can alter these results.

• Purity is often measured in percentage terms. A 100% pure sample has no impurities.
• Laboratory techniques such as filtration, distillation, and recrystallization help obtain pure samples.

A pure sample of an element, for example, would have atoms that are all identical in type, providing definitive attributes of that element.

Chemical Substance

A chemical substance is a form of matter composed of a specific arrangement of atoms or molecules. These substances have uniform properties and a definite composition.
Chemical substances surround us in our everyday life. They take the form of water, salt, sugar, and more. Identifying them can be based on their consistent and predictable properties, such as boiling or melting points.

• Each chemical substance has its own chemical formula. This formula represents the types and numbers of atoms in the substance.
• Examples of chemical substances include elements and compounds.

A pure chemical substance will have a uniform and predictable reaction when combined with another substance, making it invaluable in chemical reactions.

Type of Atom

The type of atom refers to the category of atoms that share the same number of protons in their nuclei, known as the atomic number. Elements are defined by these unique atomic numbers, and thus, the type of atom determines an element. All atoms with the same number of protons belong to the same element.

• For example, hydrogen atoms all have one proton, making them hydrogen elements.
• Different atoms can form isotopes, which have the same atomic number but different numbers of neutrons.

The type of atom profoundly influences the element's characteristics and how it interacts with other atoms.
Understanding atomic structure helps explain the periodic table, where elements are organized based on their atomic numbers and properties.