Combining Capacity or Valency of Elements
Combining Capacity or Valency of Elements
Combining capacity or Valency :
We know that the outer most shell of an atom is known as valence shell. The electrons in this outer most shell is known as valence electron. The outer most shell of an atom can accomodate maximum of eight electrons known as complete octet.
As we know that elements with complete octet are non reactive and are stable . Eg: Noble gases. Elements other than group 18 (noble gases) contain less than 8 electrons in there outer most shell.These atoms are reactive and unstable.To get stability they need to aquire the nearest noble gas configuration with the help of different reactions. During these reactions atoms either gain or lose electrons.The number of electrons lost, gained or shared by an atom determines the valency of the elements concerned. The elements those lose electrons are called as cations and elements those gain electrons are called as anions .
Valency of elements having 1-4 electrons in their outermost shells are determined by the following rule:
Valency = Number of electrons in the outermost shell
For example:
Valency = 8 - numbers of electron inthe outermost shell
For example:
The atomic numbers of three elements A, B and C are 10, 18 and 8 respectively. Identify the element which is chemically reactive? | |||
| Right Option : C | |||
| View Explanation | |||
What is the charge on an oxygen atom? | |||
| Right Option : B | |||
| View Explanation | |||
Hydrogen(H), Lithium(Li), and Sodium(Na) have ___________ electron in their outer most shells. | |||
| Right Option : B | |||
| View Explanation | |||
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