Difference Between Iodine and Iodide

Iodine, as we all know, is an important part of our lives. It is the 53rd member of the periodic family. It is represented by the symbol of I or I2, where 2 represents its diatomic form.


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It is essential to the human body so as to release hormones. The terms iodine and iodide have quite different meanings when it comes to reference with science.

Their formation requires a different number of electrons when compared to one another.

Iodine vs Iodide

The difference between iodine and iodide is that iodine is a member of the periodic family, whereas iodide is iodine when it combines with another element, such as the combination of potassium and iodine together forms potassium iodide.

Iodine vs Iodide

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Iodine is an essential element of our life both in terms of health and existence. Iodine is a necessity of the body for the development of the brain.

It also helps to produce hormones that further lessen the risk of thyroid disease. Iodine is extracted from seaweeds, activated carbon, and brines.

Iodide is a mixture of iodine with other elements such as calcium and potassium. It is particularly found in the form of salt. It is an ionic state that iodine is converted into.

When iodine and potassium come together, potassium iodide is formed, which has iodine in an ionic state which is considered to be more stable.

Comparison Table

Parameters of ComparisonIodineIodide
Number of ElectronsIt has an incomplete valance shell.It has a complete valance shell
ChargeIt has no charge and hence is neutral.It has a charge of -1.
DefinitionIt is an element.It is an ion of iodine.
DependencyIt is an independently existing element.It is an ion combine with another element.
SymbolIt has a small symbol of I.Its symbol is I^-1.

What is Iodine?

Iodine is an important member of the periodic family. Like any other element, it is found in our surroundings. This element plays an important role in our body that is of making hormones.

Thyroid hormones are released and made with the help of iodine.

Hence, lack of it can cause diseases like thyroid. This hormone further helps in the development of a strong bone and sharp mind during young age.

Its deficiency is seen worldwide in many people. Many foods contain iodine and hence should be consumed. They include fish, dairy products, salt, which is iodized, etc.

Seaweed is the best source to extract iodine. Also, many kinds of seafood help to increase iodine content in the body. Milk, cheese, and paneer are some major sources of iodine as well.

For vegetarians and vegans, prunes which are plums, can act as a source of iodine.

However, it is important to know that direct exposure to iodine can cause irritation and redness to the skin. This condition is called iodine burn.

One should always wear tight gloves and clothes while dealing with iodine in the lab. It is non-metallic and semi-shiny in color. It is solid at ordinary room temperature and becomes a liquid at 114 degrees.

Iodine is also used in various activities, especially as a salt. It is used in pharmacy supplies, coloring agents like dyes and painting colors, animal food, display of LED filters, color printing, etc.

Iodide also acts as an excellent catalyst in different types of chemical reactions. Overall, iodine plays various roles in our life both chemically and biologically.


What is Iodide?

Iodide is an ionized version of iodine. It is mostly found in a combinational state. When iodine combines with elements like potassium and calcium, it converts to an iodide state.

In an iodine atom, the number of electrons and protons are the same, but when it comes to iodide, the valance shell gains an electron from other elements to become stable and hence form iodide as it has more electrons than protons.

To be more precise, it is called an iodide ion as it now has a charge of -1. The ion is then represented by a symbol of I-1 (-1 being the charge of the ion).

Hence, iodide is not a different element but the iodine element gaining an extra electron in the valance shell in order to be stable.

This extra electron comes from the other element it combines with.

It combines with elements like sodium, potassium, calcium, which have 1 valance electron in their valance shell, making them perfect partners for making an ionic bond (bond which is made by the exchange of electron.

Another way of making the iodide ion is by sharing electrons between two iodine atoms.

In this, they share one electron among one another so as to complete the octet state, and hence individual iodide ions are formed. Together they form an iodine molecule which is represented by I2.

Main Differences Between Iodine and Iodide

  1. Iodine is an element, whereas iodide is used to represent the ion of the iodine element.
  2. Iodine can exist on its own, whereas an iodide ion is needed a separate element to donate its electron to it.
  3. Iodine does not exist independently in nature. It is mixed with any other element to form iodide.
  4. Iodine is an element, whereas iodide is not.
  5. Iodine does not have a complete octet state, whereas iodide has a complete octet state.
  1. https://www.sciencedirect.com/science/article/pii/0160412084901399
  2. https://www.sciencedirect.com/science/article/pii/0022072866800694
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