Question

show Louis dot structure and hybridization for N2

Answer 1

In Lewis dot structure, only valence electrons are used for making of the structure. Valence electrons are the electrons present in the outermost shell of the electronic configuration of an atom. The example below should shed some light on this.


Valence electrons of Nitrogen atom and Chlorine atom

If you are not good at writing electronic configurations, then there is another easy way of predicting the valence electrons by using the periodic table. Valence electrons are equal to the group number of the element in the periodic table. You can work some examples on the periodic table right now:

O belongs to group number 6 and its valence electrons are also 6.

Be belongs to group number 2 and its valence electrons are also 2.

Well, that’s step one! Easy, isn’t it?


Calculating valence electrons with the help of the periodic table

Lewis dot structure for an atom:

For neutral atoms only step one is required. Just use dots for valence electrons (outermost shell electrons) and place them as paired and unpaired around the four sides of the symbol of the atom as presented in the electronic configuration of the element. For example

Nitrogen atom:

Electronic configuration:

[He]2s22p3

Valence shell is 2s22p3 with total 5 electrons.


Lewis dot structure of N atom

Let’s do one more example:

Se atom

Electronic configuration:

[Ar]3d104s24p4

Valence shell is 4s24p4 with total 6 electrons.


Lewis dot structure of Se atom


Lewis dot structure of Cl atom


Lewis dot structure of all atoms of the main periodic table

Lewis dot structure of Monoatomic ions:

Ions are formed by gain or loss of electrons, so this will change the total number of valence electrons in the ion for the Lewis dot structure .If an atom has a negative charge it means it has gained electrons equal to the charge present on that ion, and in case of a positive charge, it has lost electrons .No of electrons lost or gained are subtracted or added from the valence electrons of the neutral atom.

For an example, let’s find the Lewis dot structure of a nitride ion ( N3-).Three negative charges means nitrogen atom has gained three electrons so its electronic configuration is with 10 electrons (instead of 7).

[He]2s22p6

Valence electrons are 8 (2 in 2s and 6 in 2p)


Lewis dot structure of Nitride ion

Now let us try Lewis dot structure of Sulfide ion ( S2-).Two negative charges means sulfur atom has gained two electrons so its electronic configuration is with 18 electrons (instead of 16).

[Ne]4s24p6

Valence electrons are 8 (2 in 3s and 6 in 3p)


Lewis dot structure of sulfide ion

Lewis dot structure will have 4 paired dots around Sulfur atom.For atoms and monoatomic ions, step one is sufficient to get the correct Lewis structure.

Lewis dot structures for Polyatomic ions and molecules :

However for molecules and polyatomic ions we need to consider many more factors before drawing a correct Lewis dot structure. Let’s practice step one “count the total valence electrons’ on molecules and polyatomic ions.

Molecule:

SO2 (Sulfur dioxide)

S is in the 6th group and O is also in the same group in the periodic table.

Total valence electrons = 6(S) + 2*6(2O) = 6+12=18

Ion:

NO3– (nitrate ion)

Total valence electrons = 5(N) + 3*6(3O) +1 (-1 charge) = 5+18+1=24

Answer 2

its the answer of ur question.