Highest q/m ratio is for:

Options

A. `He^(2+)`
B. `H^(+)`
C. `He^(+)`
D. H

Answer

To determine which ion has the highest charge-to-mass (q/m) ratio, we will analyze the given options step by step.

### Step 1: Understand the q/m Ratio
The q/m ratio is defined as the charge (q) of the ion divided by its mass (m). It is a crucial parameter in mass spectrometry and helps in identifying ions based on their behavior in electric and magnetic fields.

### Step 2: Analyze Each Ion
We will calculate the q/m ratio for each of the given ions.

#### Option 1: He²⁺ (Helium Ion)
- **Charge (q)**: 2E (where E is the elementary charge)
- **Mass (m)**: 4M (where M is the atomic mass unit)
- **q/m Ratio**:
\[ \frac{q}{m} = \frac{2E}{4M} = \frac{1}{2} \quad \text{(or 0.5)} \]

#### Option 2: H⁺ (Hydrogen Ion)
- **Charge (q)**: 1E
- **Mass (m)**: 1M
- **q/m Ratio**:
\[ \frac{q}{m} = \frac{1E}{1M} = 1 \]

#### Option 3: He⁺ (Helium Ion)
- **Charge (q)**: 1E
- **Mass (m)**: 4M
- **q/m Ratio**:
\[ \frac{q}{m} = \frac{1E}{4M} = \frac{1}{4} \quad \text{(or 0.25)} \]

#### Option 4: H (Neutral Hydrogen Atom)
- **Charge (q)**: 0E
- **Mass (m)**: 1M
- **q/m Ratio**:
\[ \frac{q}{m} = \frac{0E}{1M} = 0 \]

### Step 3: Compare the q/m Ratios
Now we will compare the calculated q/m ratios:
- He²⁺: 0.5
- H⁺: 1
- He⁺: 0.25
- H: 0

### Step 4: Identify the Highest q/m Ratio
From the comparison, we see that the highest q/m ratio is for H⁺, which is 1.

### Conclusion
The ion with the highest q/m ratio is **H⁺**.

---