The correct order of density of following elements is: -`(Be,Mg,Ca,Sr)`

Options

A. `Be gt Mg gt Ca gt Sr`
B. `Ca gt Mg gt Be gt Sr`
C. `Ca lt Mg lt Be lt Sr`
D. `Mg lt Ca lt Sr lt Be`

Answer

To determine the correct order of density for the elements Beryllium (Be), Magnesium (Mg), Calcium (Ca), and Strontium (Sr), we can follow these steps:

### Step 1: Understand the Group
These elements belong to the alkaline earth metals, which are found in Group 2 of the periodic table. The elements in this group include Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), and Barium (Ba).

**Hint:** Remember that elements in the same group often exhibit trends in properties such as density.

### Step 2: Analyze Density Trends
Generally, the density of alkaline earth metals tends to increase as you move down the group. However, there are exceptions. For the first few elements (Be, Mg, Ca), the trend is not straightforward.

**Hint:** Look for exceptions in density trends when moving down a group.

### Step 3: List the Densities
The approximate densities of the elements are as follows:
- Beryllium (Be): 1.85 g/cm³
- Magnesium (Mg): 1.74 g/cm³
- Calcium (Ca): 1.55 g/cm³
- Strontium (Sr): 2.64 g/cm³

**Hint:** Use reliable sources to find the densities of the elements for accurate comparison.

### Step 4: Compare Densities
Now, we can compare the densities:
- Beryllium (1.85 g/cm³) > Magnesium (1.74 g/cm³) > Calcium (1.55 g/cm³) < Strontium (2.64 g/cm³)

**Hint:** Arrange the elements based on their densities from highest to lowest.

### Step 5: Determine the Correct Order
From the comparison, we can see that the order of density from highest to lowest is:
1. Strontium (Sr)
2. Beryllium (Be)
3. Magnesium (Mg)
4. Calcium (Ca)

Thus, the correct order of density for the elements Be, Mg, Ca, and Sr is:
**Strontium > Beryllium > Magnesium > Calcium**

**Final Answer:** The correct order of density is: Sr > Be > Mg > Ca.