The element z = 120 would be placed in which family of periodic table :

Question

Accepted Answer

The element with atomic number z = 120 would be placed in the alkaline earth metals family of the periodic table. Here is a detailed explanation supporting this placement:

1. **Justification for Option 2 (Alkaline Earth Metals):**
   - The alkaline earth metals are located in Group 2 of the periodic table. These elements have two electrons in their outermost shell, which they tend to lose to form +2 ions. This group includes elements such as beryllium, magnesium, calcium, strontium, barium, and radium.
   - The periodic table is organized in such a way that elements are placed in groups based on their electron configuration and similar chemical properties. For element 120, its electron configuration would end in the s-block, specifically in the s^2 configuration, which is characteristic of alkaline earth metals.
   - As element 120 would follow radium (element 88) in the periodic table, it would logically be placed in Group 2, making it an alkaline earth metal.

2. **Explanation for why other options are incorrect:**
   - **Option 1 (Halogen Family):** The halogens are located in Group 17 of the periodic table. These elements have seven electrons in their outermost shell and typically gain one electron to form -1 ions. Element 120, with its s^2 configuration, does not fit the electron configuration or chemical behavior of halogens.
   - **Option 3 (Noble Gas):** Noble gases are found in Group 18 and are characterized by having a full outer electron shell, making them very stable and unreactive. Element 120, with its two valence electrons, does not have a full outer shell and thus does not belong to the noble gases.
   - **Option 4 (Alkali Metals):** Alkali metals are located in Group 1 and have one electron in their outermost shell, which they readily lose to form +1 ions. Element 120, with its two valence electrons, does not match the electron configuration of alkali metals.

In conclusion, based on the electron configuration and the organization of the periodic table, element 120 would be placed in the alkaline earth metals family, supporting Option 2 as the correct answer.