To determine which one of the given molecules is most unlikely to be formed, we need to consider the chemical properties of each molecule listed.
1. Chlorine (Cl2):
Chlorine atoms readily form diatomic molecules (Cl2) by sharing one pair of electrons, creating a single covalent bond. This is a stable and common form of chlorine found naturally.
2. Helium (He2):
Helium is a noble gas and has a complete electron shell, making it highly stable as a single atom. Noble gases typically do not form bonds with themselves or other elements under normal conditions. Therefore, the formation of He2 is highly unlikely because helium atoms do not need to share or exchange electrons to achieve stability.
3. Oxygen (O2):
Oxygen atoms readily pair up to form diatomic molecules (O2) by sharing two pairs of electrons, creating a double covalent bond. This is the most common form of oxygen found in nature.
4. Nitrogen (N2):
Nitrogen atoms form very strong diatomic molecules (N2) by sharing three pairs of electrons, creating a triple bond. This triple bond makes N2 very stable and is the most common form of nitrogen in the atmosphere.
Given these considerations:
- Cl2, O2, and N2 are all stable diatomic molecules commonly found in nature.
- He2, on the other hand, is highly unlikely to be formed due to the full valence electron shell of helium atoms, making them very unreactive and stable as single atoms.
Therefore, the molecule that is most unlikely to be formed is:
B) He2.
