Flame test is not given by

Options

A. Be
B. K
C. Sr
D. Mg

Answer

To solve the question "Flame test is not given by," we need to identify which elements from the S-block do not produce a characteristic color when subjected to a flame test. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Flame Test
The flame test is a qualitative analysis technique used to identify the presence of certain metal ions based on the color they emit when heated in a flame. Different metals produce different colors, which can be used to identify them.

**Hint:** Remember that the flame test is primarily used for identifying metals based on the colors they emit.

### Step 2: Identify the Relevant Groups
The S-block elements in the periodic table include the alkali metals (Group 1) and alkaline earth metals (Group 2). These are typically the metals that can be tested using the flame test.

**Hint:** Focus on the S-block elements, which include both alkali and alkaline earth metals.

### Step 3: Recall the Metals That Give Flame Tests
Common S-block metals that give distinct flame colors include:
- Lithium (red)
- Sodium (yellow)
- Potassium (lilac)
- Calcium (orange-red)
- Strontium (red)
- Barium (green)

**Hint:** List out the common S-block metals and their flame colors to see which ones are known to give a flame test.

### Step 4: Identify the Exceptions
Among the S-block elements, Beryllium (Be) and Magnesium (Mg) are known to not produce a characteristic color in a flame test. They do not emit a flame color that can be easily identified.

**Hint:** Look for the S-block elements that are known exceptions to the flame test.

### Step 5: Conclusion
Based on the information gathered, the elements that do not give a flame test are Beryllium (Be) and Magnesium (Mg). Therefore, the answer to the question is that the flame test is not given by Beryllium and Magnesium.

**Final Answer:** Beryllium (Be) and Magnesium (Mg) do not give a flame test.