The period number and group number of "Tantalum" (Z=73) are respectively:

Options

A. 5,7
B. 6,13
C. 6,5
D. none of these

Explanation

To determine the period number and group number of Tantalum (Z=73), we can follow these steps:

### Step 1: Identify the Atomic Number
- The atomic number of Tantalum (Ta) is given as 73.

### Step 2: Write the Electronic Configuration
- The electronic configuration of Tantalum can be determined based on its atomic number.
- The configuration is:
\[ [Xe] 4f^{14} 5d^3 6s^2 \]

### Step 3: Determine the Period Number
- The period number corresponds to the highest principal quantum number (n) in the electronic configuration.
- In Tantalum's configuration, the outermost shell is 6 (from the 6s²).
- Therefore, the period number is:
\[ \text{Period Number} = 6 \]

### Step 4: Determine the Group Number
- Tantalum is a d-block element. To find the group number for d-block elements, we use the formula:
\[ \text{Group Number} = \text{Number of electrons in } ns + \text{Number of electrons in } (n-1)d \]
- For Tantalum:
- The number of electrons in the ns subshell (6s) = 2
- The number of electrons in the (n-1)d subshell (5d) = 3
- Thus, the group number is:
\[ \text{Group Number} = 2 + 3 = 5 \]

### Final Answer
- The period number and group number of Tantalum are respectively:
\[ \text{Period Number} = 6, \quad \text{Group Number} = 5 \]

### Summary
- Period Number: 6
- Group Number: 5

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