The elements `Z = 117` and `120` have not yet have been discovered, In which family`//`group would you place these elements and also give the electronic configuration in each case.

Options

A. 17, 2
B. 17,4
C. 15,3
D. 18,2

Answer

To determine the group and electronic configuration of elements with atomic numbers 117 and 120, we will follow these steps:

### Step 1: Determine the electronic configuration of element Z = 117.
1. Start with the known electronic configuration of the preceding noble gas, Radon (Rn), which has an atomic number of 86.
2. The electronic configuration of Radon is:
\[ \text{Rn} = [Xe] 4f^{14} 5d^{10} 6s^{2} 6p^{6} \]
3. For element 117, we need to add 31 more electrons to Radon’s configuration:
- 14 electrons for 5f
- 10 electrons for 6d
- 2 electrons for 7s
- 5 electrons for 7p
4. Therefore, the electronic configuration for element 117 is:
\[ [Rn] 5f^{14} 6d^{10} 7s^{2} 7p^{5} \]

### Step 2: Determine the group of element Z = 117.
1. Since the last electron enters the p subshell, element 117 belongs to the p-block.
2. To find the group number for p-block elements, use the formula:
\[ \text{Group Number} = \text{Number of p electrons} + \text{Number of s electrons} + 10 \]
3. For element 117:
- Number of p electrons = 5 (from 7p)
- Number of s electrons = 2 (from 7s)
4. Thus, the group number is:
\[ 5 + 2 + 10 = 17 \]
5. Therefore, element 117 is in Group 17.

### Step 3: Determine the electronic configuration of element Z = 120.
1. The preceding noble gas for element 120 is Oganesson (Og), which has an atomic number of 118.
2. The electronic configuration of Oganesson is:
\[ [Rn] 5f^{14} 6d^{10} 7s^{2} 7p^{6} \]
3. For element 120, we need to add 2 more electrons to Oganesson's configuration:
- 2 electrons for 8s
4. Therefore, the electronic configuration for element 120 is:
\[ [Og] 8s^{2} \]

### Step 4: Determine the group of element Z = 120.
1. Since the last electron enters the s subshell, element 120 belongs to the s-block.
2. The group number for s-block elements is determined by the number of electrons in the outermost s subshell.
3. For element 120, there are 2 electrons in the 8s subshell.
4. Thus, element 120 is in Group 2.

### Final Answer:
- Element Z = 117: Group 17, Electronic Configuration: \[ [Rn] 5f^{14} 6d^{10} 7s^{2} 7p^{5} \]
- Element Z = 120: Group 2, Electronic Configuration: \[ [Og] 8s^{2} \]