Complete Guide to learning Valency Chart

Do you know how chemical formulas are calculated for each element? For example, have you ever wondered why the carbon dioxide formula is represented as  CO2  and not as “ COO “? All these questions can be answered by a Valency Chart.

Let’s see how we can learn most of the valency chart through the following topics.

  • Valency Chart 
  • Oxidation State 
  • Valency and Oxidation State relationship 
  • Examples of Valency 

Before we step into understanding the valency chart, let us first get oriented with the valency

What is Valency & How to determine Valency Chart?

Complete Guide to learning Valency Chart

In order to stabilize the addition between atoms of two different elements, the measuring capacity of atoms in the elements must be calculated, which is defined as Valency. For example, if atoms in the outermost orbital levels are not stable, they either break or add more atoms to stabilize themselves in order to gain sufficient energy from outside. Moreover, the chart that consists of the individual valency of all the different elements in the periodic table is called a Valency Chart of all elements.

Valency thus denotes the combination of the power of an element or radical. The valency chart lists out the valencies of the element. Valency always shows itself as a whole number and is used to chart the chemical formula of a compound. Through valency, we understand the way the atoms of one element combine with those of others.

What is the Oxidation State?

Now, let’s talk about what Oxidation State is. As mentioned before, when atoms from different elements are added together, then depending on the element and its atomic number, it will lose or gain atoms to form a chemical bond. This process is called the Oxidation State.

Difference Between Oxidation State and Valency

Now that we have a good idea about the Oxidation State and Valency of elements as part of our learning of valency chart, let us discuss briefly the multiple differences between Valency and Oxidation States.

Parameters  Valency   Oxidation State 
Definition  The maximum no of electrons an atom loses or gains in order to stabilize itself.  While oxidation is a state that is defined as the no of electrons an atom loses or gains to form a bond with a different atom. 
Representation  It is generally represented using a numerical value.  It is represented using Roman Numbers. 
Calculation  It is calculated with the help of the electronic configuration of the said element.  Whereas the Oxidation number is calculated with help of the overall charge of a coordination complex, and ligands. 
Electric Charge  Through valency electric charge cannot be found.  While oxidation the electric charge is found. 

Valency of Various Elements

As explained before, the valency of elements usually varies due to different periodic trends in oxidation states, such as Oxidation State Variation over time, within a group, etc.

Please find below the valency chart of elements

Element   Atomic Number  Valency   Oxidation State 
Hydrogen   1  1  +1,0,-1 
Helium  2  0  No Oxidation 
Lithium  3  1  +1 
Beryllium  4  2  +1,+2 
Boron  5  3  +1,+2,+3,0,-1,-3 
Carbon  6  4  +1,+2,+3,+4,0,-1,-2,-3,-4 
Nitrogen  7  3  +1,+2,+3,+4,+5,0,-1,-2,-3 
Oxygen  8  2  +1,+2,0,-1,-2 
Fluorine  9  1  -1 
Neon  10  0  0 
Sodium  11  1  +1,-1 
Magnesium  12  2  +1,+2 
Aluminium  13  3  -1,-2,+1,+2,+3 
Silicon  14  4  +1,+2,+3,+4,-1,-2,-3,-4 
Phosphorus  15  3  +1,+2,+3,+4,+5,0,-1,-2,-3 
Sulphur  16  2  +1,+2,+3,+4,+5,+6,0,-1,-2 
Chlorine  17  1  +1,+2,+3,+4,+5,+6,+7,0,-1 
Argon  18  0  0 
Potassium   19  1  +1,-1 
Calcium  20  2  +1,+2 
Scandium  21  3  +1,+2,+3 
Titanium  22  4  +,+2,+3,+4,-1,-2 
Vanadium  23  5,4  +1,+2,+3,+4,+5,-1,-3 
Chromium  24  2  +1,+2,+3,+4,+5,+6,-1,-2,-4 
Manganese  25  7,4,3  +1,+2,+3,+4,+5,+6,+7,-1,-2,-3 
Iron  26  2,3  +1,+2,+3,+4,+5,+6,-1,-2 
Cobalt  27  3,2  +1,+2,+3,+4,+5,-1,-3 
Nickel  28  2  +1,+2,+3,+4,-1,-2 
Copper  29  2,1  +1,+2,+3,+4,-2 
Zinc  30  1  +1,+2,-2 

Valency of elements – Examples of valency

Let us learn about the valency of various elements and know how to find the valency of elements. Below are the values that serve as examples of valency with respect to certain elements.

  • Nitrogen – Nitrogen with atomic number 7 and an electronic configuration of 2, 5. So makes it obvious that it has 5 electrons located in its outermost shell. It needs 3 more to complete its octet and attain stability. Therefore, the valency of nitrogen is 3.
  • Sodium –With atomic number 11 and electronic configuration, 2,8,1 sodium has to shed one electron and attain stability by completing its octet. Hence, its valency is 1.
  • Copper – Copper, a transition element denotes variable valences, two valences 1 and 2. If copper shows valency 1 or Cu(I) then it’s called Cuprous and if it presents valency 2 or Cu(II) then it’s termed as Cupric.
  • Phosphorus – Atomic number, 15, electronic configuration, 2,8,5 and thus needs 3 electrons for outermost shell and stability, making valency 3.
  • Lithium – The atomic number of lithium is 3. Its electronic configuration is 2,1, has to lose one electron to attain stability and get an electronic configuration like the noble gas Helium. Thus, its valency is 1.
  • Fluorine – Atomic number 9 with 2,7 as electronic configuration, fluorine needs one electron to accomplish the octet and attain stability. So, its valency is 1.
  • Nickel – A transition element of atomic number 28, it has variable valences 2,3 and 4 mostly.
  • Helium – Atomic number 2, outermost shell already done, this highly stable element, an inert gas or noble gas doesn’t react with other elements easily. Its valency therefore stays zero.
  • Scandium – The atomic number of scandium, a transition element, is 21. However, it does now present any variable valences and its valency is 3.

Use of the concept of valency

The valency chart is very useful in assessing how many atoms in an element will combine with those of another element,  in order to arrive at a chemical formula. Through the valency of elements, we can arrive at or have formulae of compounds. By knowing the valency of elements, it is easy to make formulae for the compounds of the respective elements.

Conclusion

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Frequently Asked Questions

Define Valency Chart

In order to stabilize the addition between atoms of two different elements, the measuring capacity of atoms in the elements must be calculated, which is defined as Valency. For example, if atoms in the outermost orbital levels are not stable, they either break or add more atoms to stabilize themselves in order to gain sufficient energy from outside. Moreover, the chart that consists of the individual valency of all the different elements in the periodic table is called a Valency Chart of all elements.

What is Valency?

Valency thus denotes the combination of the power of an element or radical. The valency chart lists the valencies of the element. Valency always shows itself as a whole number and is used to chart the chemical formula of a compound. Through valency, we understand the way the atoms of one element combine with those of others.

How the valency is calculated?

With the help of the atomic number of the element and its electronic configuration, Valency can be calculated.

Does valency have a charge?

No, the Valency of an ion is said to be equal to its charge. Which is why valency does not have a sign.

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