The total number of lone-pairs of electrons in melamine is.

Explanation

To determine the total number of lone pairs of electrons in melamine, we will follow these steps:

### Step 1: Understand the Structure of Melamine
Melamine is a compound with the chemical formula C3H6N6. It consists of a triazine ring, which is a six-membered ring containing three nitrogen atoms and three carbon atoms.

### Step 2: Draw the Lewis Structure
1. **Count the Valence Electrons**:
- Carbon (C) has 4 valence electrons, and there are 3 carbon atoms: 3 × 4 = 12 electrons.
- Nitrogen (N) has 5 valence electrons, and there are 3 nitrogen atoms: 3 × 5 = 15 electrons.
- Total valence electrons = 12 (from C) + 15 (from N) = 27 electrons.

2. **Arrange the Atoms**:
- The basic structure of melamine can be visualized as a cyclic structure with alternating nitrogen and carbon atoms.

3. **Add Bonds**:
- Connect the atoms with single and double bonds. In melamine, there are double bonds between some of the nitrogen and carbon atoms.

### Step 3: Identify Lone Pairs
1. **Assign Lone Pairs**:
- After drawing the structure, we can see that each nitrogen atom typically has one lone pair of electrons.
- In the structure of melamine, the nitrogen atoms that are bonded to hydrogen atoms (NH2 groups) will have one lone pair each.

2. **Count the Lone Pairs**:
- In melamine, there are 3 nitrogen atoms, each contributing 1 lone pair, resulting in a total of 3 lone pairs from nitrogen.
- Additionally, the nitrogen atoms involved in double bonds may not have lone pairs, depending on their bonding situation.

### Step 4: Total Lone Pairs Calculation
- After analyzing the structure, we find that melamine has a total of 6 lone pairs of electrons.

### Final Answer
The total number of lone pairs of electrons in melamine is **6**.

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