Which of the following pairs has both members from the same group of the periodic table ?

Options

A. Mg-K
B. Mg-Na
C. Na-Ba
D. Mg-Ca

Answer

To determine which of the given pairs has both members from the same group of the periodic table, we can follow these steps:

### Step 1: Understand the Structure of the Periodic Table
The periodic table is organized into rows (periods) and columns (groups). Elements in the same group share similar chemical properties and have the same number of valence electrons.

### Step 2: Identify the Groups of Each Element
We need to identify the group number for each element in the given pairs. The groups are numbered from 1 to 18.

1. **Magnesium (Mg)** - Group 2
2. **Potassium (K)** - Group 1
3. **Sodium (Na)** - Group 1
4. **Barium (Ba)** - Group 2
5. **Calcium (Ca)** - Group 2

### Step 3: Compare the Groups of Each Pair
Now, we will compare the groups of the pairs:

1. **Magnesium (Mg) and Potassium (K)**:
- Mg is in Group 2
- K is in Group 1
- **Not the same group**

2. **Sodium (Na) and Magnesium (Mg)**:
- Na is in Group 1
- Mg is in Group 2
- **Not the same group**

3. **Sodium (Na) and Barium (Ba)**:
- Na is in Group 1
- Ba is in Group 2
- **Not the same group**

4. **Magnesium (Mg) and Calcium (Ca)**:
- Mg is in Group 2
- Ca is also in Group 2
- **Same group**

### Step 4: Conclusion
The only pair that has both members from the same group is **Magnesium (Mg) and Calcium (Ca)**, which are both in Group 2.

### Final Answer
**The correct pair is Magnesium (Mg) and Calcium (Ca).**

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