The sum of total number of lone - pairs of electrons and `sp^(3)` hybridized nitrogen atoms in Melamine is

Answer

To solve the question regarding the sum of the total number of lone pairs of electrons and the number of sp³ hybridized nitrogen atoms in melamine, we will follow these steps:

### Step 1: Understand the Structure of Melamine
Melamine has the following structure:
- It consists of three nitrogen atoms and one carbon atom.
- The nitrogen atoms are connected through bonds, and some of them are involved in double bonds.

### Step 2: Draw the Lewis Structure
To visualize the lone pairs and hybridization, we can draw the Lewis structure of melamine:
- The structure shows three nitrogen atoms connected to each other and to hydrogen atoms.
- The nitrogen atoms are arranged such that two of them are bonded to two hydrogen atoms each, while one nitrogen atom is bonded to one hydrogen atom and has a double bond with another nitrogen atom.

### Step 3: Count the Lone Pairs of Electrons
- Each nitrogen atom typically has five valence electrons.
- In melamine, each nitrogen atom forms three bonds (either with hydrogen or with another nitrogen) and thus will have one lone pair of electrons.
- Therefore, for three nitrogen atoms, the total number of lone pairs is:
- Nitrogen 1: 1 lone pair
- Nitrogen 2: 1 lone pair
- Nitrogen 3: 1 lone pair
- Total lone pairs = 1 + 1 + 1 = 3 lone pairs.

### Step 4: Identify the Hybridization of Each Nitrogen Atom
- The hybridization of an atom can be determined by counting the number of sigma bonds and lone pairs.
- For the nitrogen atoms bonded to hydrogen:
- Each of these nitrogen atoms forms three sigma bonds (two with hydrogen and one with another nitrogen) and has one lone pair.
- This gives a total of 4 (3 sigma + 1 lone pair), indicating sp³ hybridization.
- The nitrogen atom involved in the double bond:
- This nitrogen forms two sigma bonds (one with hydrogen and one with another nitrogen) and has one lone pair.
- This gives a total of 3 (2 sigma + 1 lone pair), indicating sp² hybridization.

### Step 5: Count the Number of sp³ Hybridized Nitrogen Atoms
- From the above analysis, we see that there are two nitrogen atoms that are sp³ hybridized.
- Therefore, the total number of sp³ hybridized nitrogen atoms = 2.

### Step 6: Calculate the Final Sum
- The final sum is the total number of lone pairs (3) plus the number of sp³ hybridized nitrogen atoms (2):
- Total = 3 (lone pairs) + 2 (sp³ hybridized nitrogen) = 5.

### Final Answer
The sum of the total number of lone pairs of electrons and the number of sp³ hybridized nitrogen atoms in melamine is **5**.

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