Question

Give an example of what are meant by isotopes of an element. Give the nuclear symbols for each of the isotopes in your example. Tell how the isotopes are similar and how they differ.

Short answer

An example of isotopes of an element is Carbon, which has two stable naturally occurring isotopes: Carbon-12 and Carbon-13. Their nuclear symbols are \(^{\,12}\text{C}\) and \(^{\,13}\text{C}\), respectively. Isotopes of an element have the same atomic number (in this case, 6) and share the same chemical properties. However, isotopes differ in mass numbers (12 and 13 for Carbon-12 and Carbon-13) and have different numbers of neutrons. This leads to differences in some physical properties, such as density or rate of diffusion.

Step-by-step solution

Choose an element and its isotopes.

Let's choose the element Carbon as our example. Carbon has two stable naturally occurring isotopes: Carbon-12 and Carbon-13.

Identify nuclear symbols for the chosen isotopes.

To represent these isotopes using their nuclear symbols, we need to know the atomic number (the number of protons) and mass number (the number of protons and neutrons combined) for each isotope. Carbon's atomic number is 6. The mass numbers for Carbon-12 and Carbon-13 are 12 and 13, respectively. The nuclear symbol for Carbon-12 is \(^{\,12}\text{C}\) and for Carbon-13, it's \(^{\,13}\text{C}\).

Explain the similarities between the isotopes.

Isotopes of an element share some common properties: 1. Same atomic number: Both Carbon-12 and Carbon-13 have the same atomic number of 6, which means they both have 6 protons in their nucleus. 2. Same chemical properties: Since they have the same number of protons and electrons, isotopes of an element have the same chemical properties and react in the same way during chemical reactions.

Explain the differences between the isotopes.

The differences between isotopes of an element include: 1. Different mass numbers: Carbon-12 has a mass number of 12 and Carbon-13 has a mass number of 13. This means they have a different number of neutrons in their nucleus (Carbon-12 has 6 neutrons and Carbon-13 has 7 neutrons). 2. Different physical properties: Due to the difference in mass, isotopes will exhibit slightly different physical properties, such as density or rate of diffusion.

Key concepts

Nuclear Symbols

When we describe isotopes, nuclear symbols are a helpful way to visually represent specific details about them. A nuclear symbol consists of three parts: the element symbol (given by an abbreviation, like 'C' for Carbon), the atomic number, and the mass number.
The atomic number, usually written as a subscript to the left of the symbol, tells us how many protons are in the nucleus. For Carbon, this is always 6. The mass number is written as a superscript on the left, and it indicates the sum of protons and neutrons. Thus, Carbon-12 is represented as \(^{12}_{6} ext{C}\).
This format makes it simple to compare isotopes and understand the particular make-up of each one.

Atomic Number

The atomic number is crucial because it defines what element we are dealing with. Each element has a unique atomic number, which equals the number of protons in the nucleus of its atoms. For example, Carbon always has an atomic number of 6.
This means that no matter what isotope of Carbon you have, there will always be 6 protons in its nucleus. This atomic number is fundamental in identifying elements on the periodic table and understanding their properties.

Mass Number

Mass number distinguishes different isotopes of the same element. It's the sum of the number of protons and neutrons in an atom. For example, Carbon-12 has a mass number of 12 because it has 6 protons and 6 neutrons. Carbon-13, with its mass number of 13, has 6 protons and 7 neutrons.
While the atomic number remains constant across isotopes of the same element, the mass number changes because different isotopes have different numbers of neutrons. These changes in mass number can lead to differences in physical properties like weight.

Stable Isotopes

Stable isotopes do not change or decay over time, making them stable. This stability is mainly due to a balanced ratio of protons and neutrons which makes the nucleus strong and unlikely to change. For example, Carbon has two stable isotopes: Carbon-12 and Carbon-13.
Unlike unstable isotopes, which undergo radioactive decay, these stable isotopes are commonly found in nature. They retain their structure over time, which allows them to be used in various scientific applications, from tracing chemical pathways in biology to studying climatic conditions in geology.