Magnesium, achemical element with the symbol Mg and atomic number 12, is shiny grey whitesolid appearance element with the lowest melting and boiling points among all thealkaline earth metals.

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Magnesium has a greatbiological role. The important interaction between phosphate and magnesium ionsmakes magnesium a very essential element to the nucleic acid of all cells. Also, it isused as nutrition in diet, metabolism, detection in serum and plasma, therapy, etc.

You are here toknow valence electrons of a magnesium atom, aren’t you? Don’t worry along with magnesiumvalence electrons we will explain its valency also. But before that let’s havesome basic ideas about what these two terms are:

Difference BetweenValence Electrons and Valency

Valence electronsare the total number of electrons present in the outermost shell of an atom(i.e. in outermost orbital). The valence electrons for a neutral atom arealways definite, it cannot be varied (more or less) in any condition for aparticular atom and may or may not be equal to its valency.


Valency is definedas the total number of electrons an atom can lose, gain, or share at the timeof bond formation to get a stable electronic configuration i.e. to complete anoctet. The valency of an atom can be variable in different compounds orchemical reactions due to the different bonding circumstances. Most of the timevalency varies/changes due to change in oxidation and reduction states.

Magnesium (Mg)Valence Electrons

There are four simplesteps to find out the valence electrons for magnesium atom which are:

Step 1: Find theAtomic Number


To find out theatomic number of magnesium, we can use the periodic table. With the help of theperiodic table, we can easily see that the atomic number of magnesium is 12. Asits atomic number is 12, it has 12 protons, and for neutral magnesium, thenumber of protons is always equal to the number of electrons i.e. has 12electrons in its nucleus.

Step 2: WriteElectron Configuration


Electronconfiguration is the arrangement of electrons on the orbitals. The magnesiumatom has a total of 12 electrons so, we have to put 12 electrons in orbitals.The electrons will be placed in different orbitals according to the energylevel: <1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f>.Now,

Magnesium electronconfiguration Mg (12) = 3s2(completeconfiguration).

=1s22s22p63s2(condensed configuration).

Step 3: DetermineValence Shell

As we know, thevalence shell of an atom can be found from the highest number of principlequantum numbers which are expressed in the term of n, and in 3s2, thehighest value of n is 3 so that the valence shell of magnesium is3s2.

Step 4: FindValence Electrons

The total number ofelectrons present in the valence shell of an atom are called valence electrons,and there are a total of two electrons present in the valence shell of magnesium(3s2). Thus,magnesium has two valence electrons.

Valency of Magnesium(Mg)

There are manydifferent ways to find out the valency of an atom which reflects the ability ofan atom to bond with other atoms. Valence describes how easily an atom or afree radical can combine with other chemical species. The valency of an atom isdetermined based on the number of electrons lost, gained, or shared withanother atom at the time of bond formation.

An atom is said tobe stable when its outermost shells have eight electrons (except H & He).If the total number of electrons in outermost shells is between one to four,the atom has positive valency and if electrons are between four to eight, thevalency is calculated by subtracting from eight and valency will be zero. Atomshaving four outermost electrons possess both positive and negative valency, andatoms having eight outermost electrons, valency will be zero (i.e. noblegases).

Elements like magnesiumcan reach the stable state (nearest inert gas configuration: Ne) by losing twoelectrons.So that the valency of magnesium is 2.

Note: Usually, magnesiumhas a stable oxidation state of +2 most of the time but it may differ insome compounds. Do not confuse with +2 or something else (+1, +3, +4, etc.)with a positive or negative sign, it is just an oxidation number that can vary from compound to compound. But its valency is always 2 in any case.

In another sense, amagnesium atom can form a maximum of two covalent bonds in a chemical bonding (Forexample: MgO, MgCl2, MgSO4, etc.), and that what valency is, the maximum abilityto form bonds with atoms at the time of chemical bonding.

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We can also findthe valency of magnesium with the help of the periodic table. As magnesiumbelongs to group 2A (or IIA) along with beryllium (Be), calcium (Ca), strontium(Sr), barium (Ba), and radium (Ra). These group elements are also called alkalineearth metals. All these elements have valency two.