Potassium, a chemical element with a symbol K, is one of the highlyreactive alkali metals of group 1 with atomic number 11 in the periodic table. Potassiumis not found in a free state in nature due to its high reactivity behavior so that it is abstracted from different compounds (mostly from salts).
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As we know how muchpotassiumis being used in the world ofchemistry, so we must have very good proper information about its electronic properties to survive in the world of chemistry and that’s why you are here toknow what valence electrons and valency of sodium are, aren’t you? But for thisyou have to know what these two terms are, so without wasting your time let"s gofor it,
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 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 astable electronic configuration i.e. to complete an octet. The valency of an atom canbe variable in different compounds or in chemical reactions due to different bondingmechanisms.
Potassium (K) valence electrons
There are four simple steps to find out the valence electrons forpotassiumatom which are:
Step 1: Find the Atomic Number
To find out the atomic number of potassium, we can use the periodictable. With the help of the periodic table, we can easily see that the atomic number of potassiumis 19. As its atomic number is 19, it has a total of 19 protons, and forneutral potassium, the number of protons is always equal to the number of electronsi.e. 19 electrons in the nucleus.
Step 2: Write Electron Configuration
Electron configuration is the arrangement of electrons on theorbitals. The potassiumatom has a total of 19 electrons, so we have to put 11electrons in orbitals. The first two electrons will go in the 1s orbital as Sorbital can hold a maximum of two electrons only. The next two will go in 2sorbital and the next six electrons will go in 2p orbital as P orbital can onlyhold a maximum of 6 electrons. Again two electrons in 3s and six in 3p and remaining one electron will go in 4s orbital. Now wehave,
Potassium electron configuration K (19) =1s22s22p63s23p64s1(completeconfiguration) or
Step 3: Determine Valence Shell
As we know, the valence shell of an atom can be found from the highest number of principle quantum numbers which is expressed in the term of n, and in1s22s22p63s23p64s1, the highest value of n is 4 so that the valence shell of K is 4s1.
Step 4: Find Valence Electrons
The total number of electrons present in the valence shellof an atom is called valence electrons, and there is only one electron presentin the valence shell ofpotassium(4s1). Thus,potassiumhas only one valenceelectron.
Valency of Potassium (K)
There are many different ways to find out the valency of anatom which reflects the ability of an atom to bond with other atoms. Valence describeshow easily an atom or a free radical can combine with other chemical species. Thevalency of an atom is determined based on the number of electrons lost, gained, or shared with another atom.
An atom is said to be stable when its outermost shells haveeight electrons (except H and 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 is negative. Atoms having four outermost electronspossess both positive and negative valency and atoms having eight outermostelectrons have zero valencies (i.e. noble gases).
Alkali metals likepotassiumreached the stable (nearest inertgas configuration) by losing one outermost electron. So that the valency ofpotassium(K) is 1.
We can also find the valency ofpotassiumwith the help of a periodic table. as sodium is an element of group 1 which indicated alkalimetals group and valency of alkali metals are always 1.
Valence electrons and valency of K+
Potassium-ion K+ means it has lost one electron and has only18 electrons in the orbitals. The electron configuration of neutral K is1s22s22p63s23p64s1but in K+ it loses one electron, so it has a new electron configuration of1s22s22p63s23p6means K+ has only (2+6 = 8) outermost electrons which makes it stable. Thus,potassiumion (K+) has eight valence electrons.
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K+ valency is not zero like noble gas as their outermostshell has eight electrons. when apotassiumatom loses one electron, a K+ ion is produced and that’s what valency is. So that K+ valency is +1, not zero.
Chemical PropertiesPotassium (K) atom
|Number of protons||19|
|Number of electrons||19|
|Number of electrons||18|