Which of the following contains atomic number of only s-block

Options

A. 55,12, 18, 53
B. 13, 33, 54, 83
C. 3, 20, 55, 87
D. 22, 33, 55, 66

Answer

To determine which of the given atomic numbers corresponds only to s-block elements, we first need to understand what s-block elements are.

### Step 1: Identify the s-block elements
The s-block of the periodic table consists of:
- Group 1: Alkali metals (e.g., Lithium (Li), Sodium (Na), Potassium (K), etc.)
- Group 2: Alkaline earth metals (e.g., Beryllium (Be), Magnesium (Mg), Calcium (Ca), etc.)

The atomic numbers for these groups range from 1 to 88, specifically:
- Group 1: Atomic numbers 1 (H) to 87 (Fr)
- Group 2: Atomic numbers 4 (Be) to 88 (Ra)

### Step 2: List the provided atomic numbers
The atomic numbers given in the question are:
- 55
- 12
- 18
- 53
- 13
- 33
- 54
- 83
- 3
- 20
- 55
- 87
- 22
- 33
- 55
- 66

### Step 3: Identify the elements corresponding to these atomic numbers
Now, we will identify the elements corresponding to each atomic number and check if they belong to the s-block:
- 3: Lithium (Li) - s-block
- 12: Magnesium (Mg) - s-block
- 18: Argon (Ar) - not s-block
- 53: Iodine (I) - not s-block
- 13: Aluminum (Al) - not s-block
- 33: Arsenic (As) - not s-block
- 54: Xenon (Xe) - not s-block
- 83: Bismuth (Bi) - not s-block
- 20: Calcium (Ca) - s-block
- 55: Cesium (Cs) - s-block
- 87: Francium (Fr) - s-block
- 22: Titanium (Ti) - not s-block
- 66: Dysprosium (Dy) - not s-block

### Step 4: Group the atomic numbers by s-block and non-s-block
Now, we can categorize the atomic numbers:
- s-block: 3, 12, 20, 55, 87
- Non s-block: 18, 53, 13, 33, 54, 83, 22, 66

### Step 5: Determine the correct option
From the analysis, we can see that the atomic numbers that are only s-block elements are 3, 12, 20, 55, and 87.

### Conclusion
The correct answer is the group of atomic numbers that contains only s-block elements. Based on the provided options, the correct option among the choices is **C**, which contains only s-block elements.