If the atomic number of an element X is 17, then what will be the atomic number of the element lying in the same group as that of X but in the fifth period?

Options

A. 25
B. 33
C. 35
D. 53

Answer

To find the atomic number of the element lying in the same group as element X (with atomic number 17) but in the fifth period, we can follow these steps:

### Step 1: Identify the element with atomic number 17
The element with atomic number 17 is Chlorine (Cl). It is located in Group 17 of the periodic table, which is known as the halogen group.

### Step 2: Determine the group of the element
Since Chlorine is in Group 17, we are looking for the element in the same group (Group 17) but in the fifth period.

### Step 3: Identify the period
The periodic table is arranged in periods (horizontal rows). The first period has 2 elements, the second period has 8 elements, the third period has 8 elements, the fourth period has 18 elements, and the fifth period also has 18 elements.

### Step 4: Find the element in the fifth period of Group 17
In Group 17, the elements are:
- 2nd period: Fluorine (F) - Atomic number 9
- 3rd period: Chlorine (Cl) - Atomic number 17
- 4th period: Bromine (Br) - Atomic number 35
- 5th period: Iodine (I) - Atomic number 53

### Step 5: Conclusion
The element in the fifth period of Group 17 is Iodine (I), which has an atomic number of 53.

### Final Answer
The atomic number of the element lying in the same group as X but in the fifth period is **53**.

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