Formation of Ionic Compounds

Ionic Compounds

You might be wondering what happens when metals and non-metals react? Well, they form ionic bonds which form ionic compounds. An ionic bond refers to an electrostatic force of attraction between two atoms having opposite charges. An ionic bond occurs when a transfer of an electron from a metal to a non-metal takes place. An ionic bond takes place between cations and anions. Anions are ions having negative charge and cations have a positive charge. You might not be familiar with the terminology and concepts of an ionic compound but fret not, as we have got you all covered. In this article, you can learn about the ionic compound, its structure, formation, and frequently asked questions. 


What is an Ionic Compound?

You must know that each atom is unique due to its particular number of protons, neutrons, and electrons. Typically, the number of protons and electrons are equivalent to an atom. The number of protons in an atom never changes because it would mean having an entirely different element. However, the number of electrons in an atom can change. 


So, when an atom gains or loses an electron, you can get an ion. As the electrons already have a net negative charge, the charge of an atom changes when the electron gets added or removed from it. It happens because the number of electrons is no longer in sync with the protons, which have a positive charge.


Atoms that gain an electron and thus, obtain a net negative charge are nothing but anions. In contrast, atoms that lose electrons and thus, obtain a net positive charge, get called as cations. Anions tend to be non-metals while the cations tend to be metals. Also, ions may refer to a single atom or multiple, complex group of atoms.


When it comes to ions, the opposites indeed attract. The opposite charges, positive and negative hold together in ionic bonds, form ionic compounds. As the name suggests, it is nothing but the compound made of ions. The loss or gain of one atom matches with the loss or gain of the other. So, the atom donates an electron to the atom that needs it, and they form a pair.


You can consider ions as a two-bar magnet. When you try to put the south end and north end of the different magnets together, they repel each other. But, if you turn around one of the magnets, then you’re putting the north end to a sound end and magnets instantly snap together. Ions show similar behaviour, one positive and one negative ion join together to make an ionic compound. 


Properties of the Ionic Compound

  • Physical Properties: There is a strong force of attraction between positive and negative ions, which makes ionic compounds solid and not easily breakable. However, they break into pieces upon applying pressure, and that’s why they are brittle.

  • Melting and Boiling Points: Ionic compounds have a significant force of attraction between them. So, it requires a large amount of energy to break the ionic bonds between the atoms. That’s why ionic compounds have a higher melting and boiling point.

  • Solubility: Ionic compounds can dissolve in polar solvents. Water, methanol, and formamide are some examples of the polar solvents. Also, ionic compounds are insoluble or barely soluble in non-polar solvents like chloroform, hydrocarbons, etc.

  • Electric Conductivity: Ionic compounds don’t conduct electricity in solid states, but they do conduct in the molten state. As you know, conduction of electricity involves a transfer of charge from one point to another.

  • In solid - state, the movement of ions is not possible, and thus, ionic compounds can’t conduct electricity. However, ionic compounds in the molten state can conduct electricity because their electrostatic forces of attraction get overcome by the heat released.   


Structure of Ionic Compound 

The structure of an ionic compound relies on the relative size of the cations and anions. Ionic compounds include salts, oxides, sulfides, hydroxides, and most of the inorganic compounds. Ionic solids get held together by the electrostatic forces of attraction between positive and negative ions. 


When sodium ion attracts chloride ions and vice versa, you get a 3-D structure of Na+ and Cl- ions. It’s nothing but a crystal of sodium chloride. The structure doesn’t have any charge because there are equal numbers of sodium and chloride ions. The forces of attraction between ions hold the structure in place. Below is a figure to demonstrate a sodium chloride structure.


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FAQ (Frequently Asked Questions)

Question 1: Why are Ionic Compounds Usually Hard?

Answer: When metals and non-metals react, they form an ionic bond which forms ionic compounds. An ionic bond is nothing but an electrostatic force of attraction among two oppositely charged ions. There exists a strong force of attraction between positive and negative ions which enables ionic compounds to form crystals and turn into robust solids. That’s why ionic compounds become hard. Upon applying adequate pressure, they can break into small pieces quickly. This property of ionic compounds makes them brittle and hard.

Question 2: How do Ionic Compounds get Formed?

Answer: An ionic bond is formed when one atom can donate electrons to obtain the inert gas electron configuration, while the other atom needs electrons to obtain the inert gas electron configuration. It’s a chemical bond formed by the transfer of electrons from one atom to another one. Electrovalent bond is another name for these ionic bonds, and ionic compounds refer to those composed of ionic bonds. Thus, you can say ions itself form the ionic compounds. When a metal reacts with a non-metal, they form an ionic bond, and the compound gets called as the ionic compound.