Ion facts for kids
An ion is an electrically charged atom or a group of atoms. Think of it as an atom that has gained or lost some tiny particles called electrons. Because ions have an electric charge, they are attracted to or pushed away by other charged things, like electricity.
Atoms are usually neutral, meaning they have no overall electric charge. This is because they have an equal number of positively charged protons and negatively charged electrons. They also have neutrons, which have no charge.
When an atom gains or loses electrons, this balance changes. If an atom loses electrons, it becomes positively charged. If it gains electrons, it becomes negatively charged. This process of making an ion from an atom or molecule is called ionization.
For example, a normal hydrogen atom has one proton and one electron. If you heat it up, the electron can break away. Then you are left with a positively charged hydrogen ion (H+) and a free, negatively charged electron.
When ions move, they create electricity. For instance, in a wire, the metal atoms stay in place, but their electrons move, creating an electric current. Liquids that contain ions are called electrolytes. A gas with many ions is known as plasma.
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Ions in Chemistry
In chemistry, an ion is an atom or molecule that has an electric charge. This charge happens when an atom or molecule gains or loses electrons. The process of turning a neutral atom into an ion is called ionization.
Many ions do not have a color. Elements found in the main groups of the Periodic Table usually form colorless ions. However, some ions are colored. For example, transition metals often form ions that have bright colors.
Ions in Physics
In physics, very high-energy atomic parts that have lost all their electrons are called charged particles. An example of these are the particles found in alpha radiation.
Ions can be created by giving atoms a lot of energy. This can be done using voltage (electrical pressure), high-energy ionizing radiation, or very high temperatures.
A gas that has been ionized is called plasma. Plasma is often called the fourth state of matter, after solid, liquid, and gas.
Types of Ions
There are different types of ions:
- A simple ion is made from just one single atom.
- Polyatomic ions are made from a group of atoms joined together. These groups usually contain non-metal atoms, but sometimes they can include a metal atom too.
Positive and Negative Ions
Ions are named based on their charge:
- Cations are ions that have a positive charge. They are attracted to negatively charged electrodes (which are called cathodes). Most simple metal ions are cations.
- Anions are ions that have a negative charge. They are attracted to positively charged electrodes (which are called anodes). Most simple non-metal ions are anions, except for H+ (which is a proton) and NH4+.
Many ions have a charge of less than 4. However, some ions can have higher charges.
History of Ions
The idea of ions was first described by Michael Faraday in 1830. He wrote about how parts of molecules moved towards positive or negative electrodes.
Later, Svante August Arrhenius explained how this actually happened. He wrote about his ideas in his doctoral paper in 1884 at the University of Uppsala. At first, the university didn't fully accept his theory, and he barely passed his degree. But in 1903, he won the Nobel Prize in Chemistry for the very same ideas!
Word Origin
The word "ion" comes from the Greek word meaning "go."
- "Anion" means "up-goer."
- "Cation" means "down-goer."
- "Anode" means "way up."
- "Cathode" means "way down."
Images for kids
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Schematic of an ion chamber, showing drift of ions. Electrons move faster than positive ions because they are much lighter.
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Avalanche effect between two electrodes. The first ionization event releases one electron. Each time an electron hits another atom, it releases another electron, so two electrons come out of each collision.
See also
In Spanish: Ion para niños
