Cation vs. Anion

The difference between cation and anion is that cation contains a positive charge on it while an anion exhibit a negative charge on it.

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Cations vs. Anions

Cation and anion are atoms having a charge on them. Here we will come to know the differences between both of these charged particles. Cations exhibit a positive charge on them while anion exhibit a negative charge.
The word ‘cation’ is taken from the Greek word “ kata “ which means down. While the word anion is originated from the Greek word “ano” which means up. Cations are always attracted towards the cathode which is a negatively charged electrode while anions are always attracted towards the anode which is a positively charged electrode.

Cations are formed when an atom loses its one or more electrons, and hence positive charge appears on the atom which becomes cation then. An anion is formed when an atom gains one or more electrons and thus become negatively charged. Cations are formed from the atoms of metals while anions are formed from the elements of nonmetals. In cations, the number of protons is more than the number of electrons, and that is why it shows a positive charge. In the anion, the number of electrons is greater than protons, and that is why they exhibit negative charge.

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In a chemical reaction, cations react with anions to form an ionic compound. A cation can never react with a cation, and an anion can never react with an anion. The radius of a cation is always greater than the radius of an anion because, in cations, orbits are lost with the loss of electrons while in anions, orbit number is increased with the gain of electrons. A cation which exhibits a positive charge is denoted with a superscript + after the name of the element or chemical formula of a compound, e.g., Fe2+ and NH4+. An anion is also denoted in the same way with a superscript of – after the name of the element or chemical formula of a compound, e.g., Br-  N3- etc. The examples of cations are iron (Fe2+ and Fe3+), Sodium (Na+), potassium (K+) and magnesium (Mg2+) . The examples of anions are chloride (Cl-), Flouride (F-), bromide (Br-), hydride (H-) and nitride (N-).

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Comparison Chart

Basis Cation Anion
Definition They are the type of particles which exhibit positive charge.They are the type of particles which exhibit negative charge.
Why they possess charge ? They possess a positive charge because they lose one or more electrons.They possess a negative charge because they gain one or more electrons.
Origination of words The word cation is originated from the Greek word “kata” which means down.The word anion is originated from the Greek word “ano” which means down.
Electron to proton ratio They exhibit a positive charge because the number of protons is greater than the number of electrons in themThey exhibit a negative charge because the number of the electron is greater than the number of proton in them.
Type of atoms They are formed from the atoms of metalsThey are formed from the atoms of nonmetals.
Attraction towards electrodes They are attracted towards the negatively charged electrode, i.e. cathode.They are attracted towards the positively charged electrode, i.e. anode.
How they are denoted They are denoted by the superscript + after the name of the element or chemical formula of the compound.They are denoted by the superscript – after the name of the element or chemical formula of the compound.
Radius The radius of cations is smaller because the number of orbits becomes less due to the loss of electronsThe radius of anions is larger than the radius of cations because the number of orbits is increased with the gain of electrons.
Chemical reaction In a chemical reaction, they react with anions to form ionic compoundsIn a chemical reaction, they react with cations to form ionic compounds.
Do not react with They do not attract or react with positively charged particlesThey do not attract or react with positively charged particles
Examples The examples of cations can be given as Iron (Fe2+ and Fe 3+), calcium (Ca2+), potassium (K+), aluminium Al3+) and ammonium ion (NH4+) etc.The examples of anions can be given as bromide (Br-), chloride (Cl-) , nitride (N-) and hydride (H-), etc.

What are cations?

Cations are positively charged particles. They are formed when an atom of an element loses one or more electrons. Atoms do so to gain stability. In other words, they want to get the order of noble gases which are the most stable elements in the universe. The word cation is originated from the Greek word “kata” which means down. In a cation, the number of protons is greater than that of electrons. As we know, protons possess a positive charge and electrons possess a negative charge. Due to the higher number of positively charged particles, cations show positive charge. Cations are always formed from the atoms metals. The reason being is that metals have a tendency to lose electrons. A metallic surface has a countless number of free electrons on it. Thus metals lose electrons, and their atoms exist in the form of cations.

Cations are always attracted towards cathode that is a negative electrode. In a chemical reaction, cations always react with anions to form ionic compounds. One best example of this type of reaction is the formation of common salt, i.e., sodium chloride (NaCl)  in which sodium is a cation and chloride is an anion. The examples of cations can be given as sodium (Na+), potassium (K+), lithium (Li+), magnesium (Mg2+) and aluminum (Al3+). An example among positively charged compounds is of ammonium ion (NH4+).

What are anions?

Anions are the atoms which possess a negative charge. They exhibit a negative charge because the atoms gain one or more electrons to gain stability. Thus the number of electrons becomes greater than the number of protons in those atoms, and they show a negative charge. Mostly the atoms of nonmetals show this tendency. They exhibit this type of behavior in order to follow the noble gases which are the most stable element of this universe.

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Anions are always attracted towards the positive electrode, the, i.e. anode. In a chemical reaction, anions react with cations to form ionic compounds. The word anion is originated from the Greek word “ano” which means up. The examples of anions can be given as sulfur (S-), Iodide ion (I-), bromide (Br-), chloride (Cl-), hydride (H-) and nitride (N-).

Key differences

  1. Cations are those particles which possess positive charge while anions are those particles which possess a negative charge.
  2. Cations have a tendency to move towards a negative electrode, i.e., cathode while anions have a tendency to move towards the positive electrode, i.e., the anode.
  3. In cations, protons are more in number than electrons while in anions, electrons are more in number than protons.
  4. Cations are formed by the atoms of metallic elements while anions are formed from the atoms of nonmetallic elements.
  5. The orbits of anions are larger than the orbits of cations.

Conclusion

Cations and anions, both are charged particles. It is very important for science students to know the differences between both of them. In the above article, we learned clear differences between cations and anions.

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