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 (Ta, Z=73), we can follow these steps:

### Step 1: Write the Electronic Configuration
The first step is to write the electronic configuration of Tantalum. The atomic number of Tantalum is 73, which means it has 73 electrons. The electronic configuration can be determined as follows:

1. Start with the nearest noble gas, which is Xenon (Xe, atomic number 54).
2. After Xenon, we fill the orbitals in the following order:
- 6s²
- 4f¹⁴
- 5d³

Thus, the complete electronic configuration of Tantalum is:
\[ \text{Xe} \, 6s^2 \, 4f^{14} \, 5d^3 \]

### Step 2: Determine the Period Number
The period number corresponds to the highest principal quantum number (n) in the electronic configuration.

- In the configuration \(6s^2 \, 4f^{14} \, 5d^3\), the highest value of n is 6 (from the 6s subshell).

Therefore, the period number of Tantalum is **6**.

### Step 3: Determine the Group Number
To find the group number for Tantalum, we consider the d-block elements. The group number can be calculated using the formula:
\[ \text{Group Number} = \text{Number of } ns \text{ electrons} + \text{Number of } (n-1)d \text{ electrons} \]

1. From the electronic configuration:
- The number of electrons in the ns subshell (6s) = 2
- The number of electrons in the (n-1)d subshell (5d) = 3

2. Adding these together:
\[ \text{Group Number} = 2 + 3 = 5 \]

Thus, the group number of Tantalum is **5**.

### Final Answer
The period number and group number of Tantalum are respectively **6** and **5**.

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