Lewis Symbols are used for representing electrons in the highest energy level of an atom. For example – The sodium atom has one electron in its highest energy level so its Lewis symbol is Na•, dot around Sodium Atomic Symbol Na representing a single electron.
Let’s now see how to draw Lewis Symbols.
How to draw Lewis Symbols?
In order to draw Lewis Symbol of any atom or molecule, you need to know what’s its electronic configuration? So as to find number of electrons in the highest energy shell. So follow below steps for drawing lewis symbol of an atom.
- Write Electronic Configuration of the atom
- Find shell which have highest energy, usually outermost shell
- Take symbol of atom and then put as many dots around it as there are electrons in highest energy shell
That’s it, this is how to draw Lewis Symbol of an atom.
For example – Let’s draw the lewis symbol of Carbon.
Electronic configuration of carbon is [He] 2s2 2p2. So Carbon atom have four electrons in its outermost shell(2). That’s why lewis symbol of Carbon will be carbon atomic symbol C surrounded by four dots.
Why Lewis Symbols are important?
- Lewis Symbols can be useful for understanding how an atom will react with other atoms
- Lewis Symbols can be used for making structures of molecules which are also known as Lewis Structures
- Lewis Symbols can be used for describing chemical reactions using Chemical Equations
Some examples of Lewis Symbol
Let’s draw lewis symbols of Chlorine, Aluminium and Calcium atoms. Firstly we need to write their electronic configurations.
|Atom||Electronic Configuration||Number of electrons in Outermost Shell|
|Chlorine||[Ne] 3s2 3p5||7|
|Aluminium||[Ne] 3s2 3p1||3|
Lewis Symbol of Chlorine
Chlorine have electronic configuration [Ne] 3s2 3p5, so it have 7 valence electrons. So for drawing lewis symbol of Chlorine, just place 7 dots around the atomic symbol of Chlorine Cl.
Lewis Symbol of Aluminium
Aluminium have electronic configuration [Ne] 3s2 3p1, so it have 3 valence electrons. So for drawing lewis symbol of Aluminium, just place 3 dots around the atomic symbol of Aluminium Al.
Lewis Symbol of Calcium
Calcium have electronic configuration [Ar] 4s2, so it have 2 valence electrons. So for drawing lewis symbol of Calcium, just place 2 dots around the atomic symbol of Calcium Ca.