Is Sodium Chloride NaCl Ionic or Covalent or Metallic?
Sodium Chloride NaCl is a purely ionic bond neither covalent nor metallic. It is a bond that exists between metal and non-metal. In this compound, (Na) sodium is a metal, and chlorine(Cl) is a non-metal. It is a more stable compound as there is a high electrostatic force of attraction between the two opposite charges.
In the formation of sodium chloride (NaCl), the Sodium atom (Z=11) has one valence electron (2, 8, 1). Similarly, the chlorine atom (Z=17) has a 7 valence electron (2,8,7). The sodium atom loses its only valence electron and changes Na+ ion (cation). This electron accepts by a chlorine atom which changes to a Cl– ion (anion). Both of these ions are mutually attracted to form a NaCl molecule.
As we said earlier sodium chloride is an ionic bond. The purpose of each atom is to achieve stability. Stability can be achieved only if the outermost electron shell is completely filled. The capacity of the outermost shell is a maximum of 8 electrons. Let’s see further.
A chemical bond is a force that holds the atoms together in a molecule. It implies the force of attraction and repulsion balanced at a particular point. Atoms combine together because
To acquire noble gas configuration: Noble gases have eight electrons in their valence shells. The atoms of elements other than noble gases combine with other atoms to achieve eight electrons. This tendency of atoms to acquire eight electrons in the valence shell is called the octet rule. This rule was given by Lewis. However, this rule is not universally applicable few exceptions exist.
To acquire a state of minimum energy: According to the modern theory of chemical bonding, atoms form chemical bonds so as to have minimum energy and maximum stability. A molecule in a lesser energy state is more stable than isolated atoms.
How sodium chloride NaCl is ionic Not covalent bond?
You should remember that Ionic bonds are generally formed with a combination of metals and nonmetals. The metal atom loses one or more electrons present in its valence shell and these electrons accept by the non-metallic atom.
One of the species is a cation and the other is an anion. Here, Sodium is acting as a cation, and chlorine is acting as an anion. By losing electrons, the metal atom changes to a (positive ion) cation. Similarly, the nonmetal atom gaining the electrons, get changes to a (negative Ion) anion. The oppositely charged ions attract each other.
It should be noted that an atom loses electrons to achieve the nearest noble gas. For example, if sodium loses one electron it will achieve the nearest noble gas neon that has the configuration of 2,8.
However, after giving up the electron the sodium atom is no more electrically neutral. It has 11 protons in its nucleus but only 10 electrons are revolving around it. Therefore, it has a net positive charge of +1, this positive charge atom is called a sodium ion. It is written as Na+.
On the other hand, after acquiring an electron from sodium, the chlorine atom also does not remain electrically neutral. It has one more electron than the number of protons in the nucleus it is, therefore, a negative charge chloride ion Cl–. Both of these ions Na+ and Cl- are attracted towards each other due to the electric charge forms an ionic bond.
Keeping Concise, Na+ ion has the configuration of Neon Ne while Cl– ion represents the configuration of Argon Ar. Both are inert gas atoms. Now, These atoms take part in chemical combination or bond formation in order to complete the octet( 8 electrons in valence shell) and achieve the electronic configuration of the nearest noble gas atom.
Characteristics of ionic compounds
- Ionic compounds have high melting and boiling point.
- In solid state, ionic compounds are bad conductors of electricity. However, in molten state or in the form of aqueous solution, they conduct electricity.
- Ionic compounds are polar in nature. Hence, these are soluble in polar solvents like water.
- These compounds do not possess directional characteristics and hence do not show stereoisomerism.
- Ionic compounds are hard and brittle.
Are Properties of Sodium and Chlorine the same as Sodium Chloride
It is interesting to know that electrons in both of these atoms play a vital role. Properties get changed as the atom loses an electron. A neutral sodium atom (Na) colour is silvery white whereas sodium cation (Na+) becomes colourless. Similarly, earlier neutral sodium atom has a toxic property. It becomes non-poisonous on losing an electron.
If we consider chlorine atom, earlier its color was yellowish-green. When it gains the electron from the sodium, it changes to colorless. Chlorine taste was poisonous, on becoming chloride Cl– and it becomes non-poisonous.
NaCl sodium chloride belongs to the ionic compound category. Ionic compounds are crystalline solids in which ions are arranged in a certain definite pattern to form a crystal lattice. In sodium chloride, each sodium ion is surrounded by six chloride ions and each chloride ion by six sodium ions, thus giving rise to a three-dimensional crystal structure. Whereas, covalent bonds usually consist of individual molecules rather than crystalline giant structures, unlike ionic bonds.
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