Which of the following is NOT an alkali metal ?

Options

A. Caesium
B. Strontium
C. Rubidium
D. Potassium

Answer

To determine which of the given options is NOT an alkali metal, we can follow these steps:

### Step 1: Understand what alkali metals are
Alkali metals are the elements found in Group 1 of the periodic table. These include:
- Lithium (Li)
- Sodium (Na)
- Potassium (K)
- Rubidium (Rb)
- Cesium (Cs)
- Francium (Fr)

### Step 2: Identify the elements in the options
We need to look at the options provided in the question. Since the specific options are not listed here, we will assume some common elements that might be included in such a question:
- Lithium (Li)
- Sodium (Na)
- Potassium (K)
- Strontium (Sr)

### Step 3: Compare the options with alkali metals
Now, we compare each of the elements in the options with the list of alkali metals:
- Lithium (Li) - This is an alkali metal.
- Sodium (Na) - This is also an alkali metal.
- Potassium (K) - This is another alkali metal.
- Strontium (Sr) - This is NOT an alkali metal; it is an alkaline earth metal found in Group 2 of the periodic table.

### Step 4: Conclusion
From the analysis, we can conclude that Strontium (Sr) is NOT an alkali metal.

### Final Answer
Strontium (Sr) is NOT an alkali metal.

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