Isotopes of oxygen facts for kids

Oxygen is a super important element! It's in the air we breathe and the water we drink. But did you know that oxygen can come in different "flavors" called isotopes? Think of isotopes like different versions of the same car model. They look similar, but they have tiny differences inside.

The main difference between oxygen isotopes is how many neutrons they have in their atom's center, called the nucleus. The number of protons always stays the same for oxygen (8 protons), but the number of neutrons can change.

Stable Oxygen Isotopes

There are three main types of oxygen isotopes that are stable. This means they don't change over time. They are:

• Oxygen-16 (written as ¹⁶O)
• Oxygen-17 (written as ¹⁷O)
• Oxygen-18 (written as ¹⁸O)

Oxygen-16 is the most common type of oxygen found on Earth. It has 8 protons and 8 neutrons. Oxygen-17 has 8 protons and 9 neutrons, and Oxygen-18 has 8 protons and 10 neutrons. These tiny differences are very useful for scientists!

How Scientists Use Oxygen Isotopes

Scientists use the different amounts of oxygen isotopes to learn about many things. For example, they can study:

• Past Climates: The ratio of Oxygen-18 to Oxygen-16 in ice cores or ancient shells can tell us how warm or cold the Earth was thousands of years ago.
• Water Cycles: They can track how water moves through the environment, from oceans to clouds to rain.
• Biology: Isotopes help understand how plants and animals use oxygen in their bodies.

Unstable Oxygen Isotopes (Radioisotopes)

Besides the stable isotopes, oxygen also has many unstable isotopes. These are called radioisotopes. Unlike stable isotopes, radioisotopes are not permanent. They slowly change over time, giving off energy. This process is called radioactive decay.

Oxygen radioisotopes range from ¹¹O to ²⁶O. They all have very short half-lives. A half-life is the time it takes for half of the atoms in a sample to decay.

• The longest-lived oxygen radioisotope is Oxygen-15 (¹⁵O). It has a half-life of about 122 seconds, which is just over two minutes.
• The shortest-lived oxygen radioisotope is Oxygen-12 (¹²O). It has an incredibly short half-life, less than a tiny fraction of a second!

Scientists use these short-lived radioisotopes in special ways, like in medical imaging (for example, in PET scans) to see inside the human body.

See also

In Spanish: Anexo:Isótopos de oxígeno para niños