Argon, a chemical element with the symbol Ar and atomic number 18,is a colorless, odorless, tasteless, non-flammable, nontoxic inert gas. It isthe third most abundant gas on the earth"s atmosphere (abundance is morethan twice water vapor).
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Its main isotopes are 40Ar (99.6%), 36Ar (0.34%) and 38Ar (0.06%)found on the earth"s surface. Although it is a noble gas, it can form various compoundsunder various standard extreme conditions. Argon fluorohydride (HArF), tungstenpentacarbonyl
You are here to know valence electrons and valency of argon,aren’t you? But before that let"s have some ideas about what these two terms are:
Difference Between Valence Electrons and Valency
Valence electrons are the total number of electrons presentin the outermost shell of an atom (i.e. in outermost orbital). The valenceelectrons for a neutral atom is always definite, it cannot be varied (more orless) in any condition for a particular atom and may or may not be equal to itsvalency.
Valency is defined as the total number of electrons an atomcan lose, gain, or share at the time of bond formation to get a stableelectronic configuration i.e. to complete an octet. The valency of an atom canbe variable in different compounds or chemical reactions due to the differentbonding circumstances. Most of the time valency varies/changes due to change inoxidation and reduction states.
Argon (Ar) Valence Electrons
There are four simple steps to find out the valenceelectrons for argon atom which are:
Step 1: Find the Atomic Number
To find out the atomic number of argon, we can use theperiodic table. With the help of the periodic table, we can easily see that theatomic number of argon is 18. As its atomic number is 18, it has 18 protons,and for neutral argon, the number of protons is always equal to the number ofelectrons i.e. has 18 electrons in its nucleus.
Step 2: Write Electron Configuration
Electron configuration is the arrangement of electrons onthe orbitals. The argon atom has a total of 18 electrons so, we have to put 18 electrons in orbitals. The electrons will be placed in orbital according to this energy levels: <1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f>. Now,
Argon electron configuration Ar (18) =1s22s²2p⁶3s²3p⁶(completeconfiguration)
Step3: Determine Valence Shell
As we know, the valence shell of an atom can be found fromthe highest number of principle quantum numbers which is expressed in the termof n, and in
Step 4: Find Valence Electrons
The total number of electrons present in the valence shellof an atom is called valence electrons, and there are eight electrons presentin the valence shell of argon (3s²3p⁶). Thus, argon has eight valence electrons.
Valency of Argon (Ar)
There are many different ways to find out the valency of anatom which reflects the ability of an atom to bond with other atoms. Valencedescribes how easily an atom or a free radical can combine with other chemicalspecies. The valency of an atom is determined based on the number of electronslost, gained, or shared with another atom at the time of bond formation.
An atom is said to be stable when its outermost shells haveeight electrons (except H & He). If the total number of electrons inoutermost shells is between one to four, the atom has positive valency and ifelectrons are between four to eight, the valency is calculated by subtractingfrom eight and valency will be zero. Atoms having four outermost electronspossess both positive and negative valency, and atoms having eight outermostelectrons, valency will be zero (i.e. noble gases).
Noble gases like argon have eight valence electrons so itdoes not require to lose or gain electrons to complete its energy shell i.e. stableoctet. So that they do not have any tendency to combine with other elementswhich makes the valency of argon zero. Because valency is all about lose, gain, orshare of electrons.
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We can also find the valency of argon with the help of the periodictable. As argon belongs to group 8A which are groups of noble gases having valencyzero.