The sum of the number of lone pairs of electrons on each central atom in the following species is
`[TeBr_(6)]^(2-), [BrF_(2)]^(+) and [XeF_(3)]^(-)`
(Atomic number : F = 9, Br = 35, Te = 52, Xe = 54)

Answer

To solve the problem, we need to determine the number of lone pairs of electrons on the central atom for each of the given species: \([TeBr_6]^{2-}\), \([BrF_2]^{+}\), and \([XeF_3]^{-}\).

### Step 1: Analyze \([TeBr_6]^{2-}\)

1. **Identify the central atom**: The central atom is Tellurium (Te).
2. **Determine the valence electrons**: Te has 6 valence electrons (Group 16).
3. **Calculate total electrons**: The charge of \(2-\) indicates that there are 2 additional electrons. Therefore, total electrons = 6 (from Te) + 2 (from charge) = 8 electrons.
4. **Count bonding pairs**: Te is bonded to 6 Bromine (Br) atoms. Each bond uses 1 pair of electrons (2 electrons). Thus, 6 bonds use 6 pairs (12 electrons).
5. **Calculate lone pairs**: Since Te has 8 electrons available and 12 are used in bonding, it will have 1 lone pair (8 - 6 = 2 electrons left, which form 1 lone pair).

### Step 2: Analyze \([BrF_2]^{+}\)

1. **Identify the central atom**: The central atom is Bromine (Br).
2. **Determine the valence electrons**: Br has 7 valence electrons (Group 17).
3. **Calculate total electrons**: The charge of \(+\) indicates that there is 1 less electron. Therefore, total electrons = 7 (from Br) - 1 (from charge) = 6 electrons.
4. **Count bonding pairs**: Br is bonded to 2 Fluorine (F) atoms. Each bond uses 1 pair of electrons (2 electrons). Thus, 2 bonds use 2 pairs (4 electrons).
5. **Calculate lone pairs**: Since Br has 6 electrons available and 4 are used in bonding, it will have 1 lone pair (6 - 4 = 2 electrons left, which form 1 lone pair).

### Step 3: Analyze \([XeF_3]^{-}\)

1. **Identify the central atom**: The central atom is Xenon (Xe).
2. **Determine the valence electrons**: Xe has 8 valence electrons (Group 18).
3. **Calculate total electrons**: The charge of \(-\) indicates that there is 1 additional electron. Therefore, total electrons = 8 (from Xe) + 1 (from charge) = 9 electrons.
4. **Count bonding pairs**: Xe is bonded to 3 Fluorine (F) atoms. Each bond uses 1 pair of electrons (2 electrons). Thus, 3 bonds use 3 pairs (6 electrons).
5. **Calculate lone pairs**: Since Xe has 9 electrons available and 6 are used in bonding, it will have 1 lone pair (9 - 6 = 3 electrons left, which form 1 lone pair).

### Step 4: Sum the lone pairs

- Lone pairs from \([TeBr_6]^{2-}\): 1 lone pair
- Lone pairs from \([BrF_2]^{+}\): 1 lone pair
- Lone pairs from \([XeF_3]^{-}\): 1 lone pair

**Total lone pairs = 1 + 1 + 1 = 3 lone pairs.**

### Final Answer:
The sum of the number of lone pairs of electrons on each central atom in the species is **3**.

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