9. Element X is in Group 2 and element Y is in Group 17. What happens when a compound is formed between these two atoms?

When a compound is formed between element X (in Group 2) and element Y (in Group 17), an ionic bond is typically formed. This is because element X, being in Group 2, has two valence electrons that it can lose to achieve a stable electron configuration, while element Y, being in Group 17, has seven valence electrons and needs one more electron to achieve stability. Therefore, element X donates its two electrons to element Y, resulting in the formation of a compound with a positive charge on element X and a negative charge on element Y. This ionic bond creates an electrostatic attraction between the oppositely charged ions, holding the compound together.