How many of these metals can show `+3` oxidation state also.
`Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn`

Answer

To determine how many of the given metals can show a +3 oxidation state, we will analyze each metal based on its electronic configuration and the typical oxidation states it can exhibit.

### Step-by-Step Solution:

1. **Identify the Metals**: The metals given are Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), and Zinc (Zn).

2. **Determine Electronic Configurations**:
- Scandium (Sc): Atomic number 21 → [Ar] 4s² 3d¹
- Titanium (Ti): Atomic number 22 → [Ar] 4s² 3d²
- Vanadium (V): Atomic number 23 → [Ar] 4s² 3d³
- Chromium (Cr): Atomic number 24 → [Ar] 4s² 3d⁵
- Manganese (Mn): Atomic number 25 → [Ar] 4s² 3d⁵
- Iron (Fe): Atomic number 26 → [Ar] 4s² 3d⁶
- Cobalt (Co): Atomic number 27 → [Ar] 4s² 3d⁷
- Nickel (Ni): Atomic number 28 → [Ar] 4s² 3d⁸
- Zinc (Zn): Atomic number 30 → [Ar] 4s² 3d¹⁰

3. **Analyze Possible Oxidation States**:
- **Scandium (Sc)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Titanium (Ti)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Vanadium (V)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Chromium (Cr)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Manganese (Mn)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Iron (Fe)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Cobalt (Co)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Nickel (Ni)**: Can lose 3 electrons (2 from 4s and 1 from 3d) → +3 oxidation state possible.
- **Zinc (Zn)**: Has a fully filled d-subshell (3d¹⁰), so it can only lose 2 electrons (from 4s) → +2 oxidation state only.

4. **Count the Metals with +3 Oxidation State**:
- The metals that can exhibit a +3 oxidation state are: Sc, Ti, V, Cr, Mn, Fe, Co, Ni.
- Total = 8 metals.

### Final Answer:
**8 metals can show +3 oxidation state.**

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