To determine which pair of elements is most likely to form an ionic bond, we need to consider the nature of ionic bonds themselves. Ionic bonds typically form between a metal and a non-metal where one atom donates an electron and the other accepts it.
Let’s analyze the given pairs:
- a) Carbon and Oxygen: Both carbon and oxygen are non-metals. They are more likely to share electrons and form covalent bonds rather than transferring electrons.
- b) Sodium and Fluorine: Sodium is a metal and fluorine is a non-metal. Sodium tends to lose one electron easily and fluorine tends to gain one electron, making this pair a strong candidate for ionic bonding.
- c) Sulfur and Hydrogen: Both sulfur and hydrogen are non-metals. They would likely share electrons, thereby forming a covalent bond rather than an ionic bond.
- d) Phosphorus and Oxygen: Both phosphorus and oxygen are non-metals. Similar to the previous examples, they are more likely to form covalent bonds through sharing electrons.
Given this analysis, the pair of elements that is most likely to form an ionic bond is sodium and fluorine (b).