Firstly, the atom is defined as the smallest unit of matter and has subatomic particles as mentioned below:
Protons: They are positively charged particles.
Neutrons: They are neutral particles.
Electrons: They are negatively charged particles present in the orbits outside the nucleus.
Ion
An ion is an electrically charged atom or molecule that results from the loss or gain of one or more electrons. Atoms are neutral and have an equal number of protons and electrons. However, if an atom gains or loses an electron, it becomes charged and is called an ion.
When the number of protons is equal to the number of electrons it is considered a neutral atom. This means that to balance every negative charge there is a positive charge for it. But in some cases, the number of electrons may exceed the number of protons or vice-versa which creates an imbalance within the atom’s charge and thus forms an ion.
Types of Ions
There are two types of ions
1. Cations
2. Anions
Cations
A cation is a positively charged ion that has lost one or more electrons from its outermost shell. This loss of electrons leaves the cation with a net positive charge. Cations are typically formed from metal atoms that have low ionization energies, which means they are easily able to lose electrons. For example, sodium (Na) loses one electron to become a cation with a charge of +1 (Na+), while calcium (Ca) loses two electrons to become a cation with a charge of +2 (Ca2+).
They have several characteristics, including:
1.Positive charge: Cations have a positive charge due to the loss of electrons, which gives them a net positive charge.
2.Smaller size: Cations are generally smaller in size than the neutral atom from which they are formed. This is because the loss of electrons reduces the number of electrons in the electron cloud, leading to a decrease in atomic size.
3.High reactivity: Cations are highly reactive due to their positive charge. They can easily react with anions or other species that have a negative charge, forming ionic compounds.
4.Mobility: Cations can move freely in a solution or in a vacuum under the influence of an electric field. This makes them important in electrochemical reactions and in electrolysis.
5.Attraction to anions: Cations are attracted to anions, which have a negative charge, due to electrostatic forces. This attraction plays a crucial role in many chemical reactions.
Anions
An anion is a negatively charged ion that has gained one or more electrons into its outermost shell. This gain of electrons leaves the anion with a net negative charge. Anions are typically formed from nonmetal atoms that have high electronegativities, which means they are easily able to attract electrons. For example, chlorine (Cl) gains one electron to become an anion with a charge of -1 (Cl-), while oxygen (O) gains two electrons to become an anion with a charge of -2 (O2-).
They have several characteristics, including:
1.Negative charge: Anions have a negative charge due to the gain of electrons, which gives them a net negative charge.
2.Larger size: Anions are generally larger in size than the neutral atom from which they are formed. This is because the gain of electrons increases the number of electrons in the electron cloud, leading to an increase in atomic size.
3.Low reactivity: Anions are less reactive than cations due to their negative charge. They can easily react with cations or other species that have a positive charge, forming ionic compounds.
4.Mobility: Anions can move freely in a solution or in a vacuum under the influence of an electric field. This makes them important in electrochemical reactions and in electrolysis.
5.Attraction to cations: Anions are attracted to cations, which have a positive charge, due to electrostatic forces. This attraction plays a crucial role in many chemical reactions.
Differences Between Cations & Anions
Cations and anions are two types of ions with opposite charges. Cations have a positive charge, while anions have a negative charge. The main difference between cations and anions is their charge and the way they are formed.
Cations are formed when an atom loses one or more electrons, resulting in a positive charge. Cations are typically formed by metals, which tend to lose electrons in chemical reactions. For example, sodium (Na) loses one electron to form a cation with a charge of +1 (Na+).
Anions, on the other hand, are formed when an atom gains one or more electrons, resulting in a negative charge. Anions are typically formed by nonmetals, which tend to gain electrons in chemical reactions. For example, chlorine (Cl) gains one electron to form an anion with a charge of -1 (Cl-).
Cations and anions are attracted to each other due to their opposite charges and form ionic compounds when they combine. In an ionic compound, the cation and anion are held together by an electrostatic force of attraction called an ionic bond.
In summary, cations and anions are two types of ions with opposite charges, formed by the loss or gain of electrons. Cations have a positive charge and are typically formed by metals, while anions have a negative charge and are typically formed by nonmetals.
Naming of Cation & Anion
Cations are positively charged ions. The term "cation" comes from the Greek word "kata," which means "down." This refers to the fact that cations are attracted to the negative electrode, or cathode, in an electric field. In 1834, Michael Faraday used the term "anode" to refer to the positive electrode, which completed the terminology for the two types of charged particles.
Anions, on the other hand, are negatively charged ions. The term "anion" comes from the Greek word "ana," which means "up." This refers to the fact that anions are attracted to the positive electrode, or anode, in an electric field.
The discovery of cations and anions dates back to the early 19th century when scientists were studying the behavior of electricity. In 1833, Michael Faraday, an English physicist and chemist, discovered that when an electric current was passed through a solution of salt, the solution was separated into two parts. One part of the solution had a positive charge, while the other had a negative charge. Faraday called these two parts of the solution "ions," from the Greek word "ion," which means "going."
Later, Faraday found that when a salt was dissolved in water, the resulting solution contained positively charged particles that he called "cations." These cations were attracted to the negative electrode, or cathode, in an electric field. Faraday also discovered that the solution contained negatively charged particles that he called "anions." These anions were attracted to the positive electrode, or anode, in an electric field.
Faraday's work on cations and anions laid the groundwork for the development of the concept of electrolysis, which is the process of using an electric current to drive a chemical reaction. Electrolysis has many practical applications, including electroplating, the production of aluminum, and the production of chlorine gas. Today, the study of cations and anions is an important part of many fields, including chemistry, physics, and materials science.
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