Final answer:
Group 1 elements, which need to lose one electron, bond easily with Group 17 elements, which need to gain one electron, forming ionic bonds.
Step-by-step explanation:
Group 1 elements bond easily with Group 17 (7A) elements. The elements in Group 1, which are known as alkali metals, have one electron in their outermost shell and tend to lose one electron to achieve a full valence shell, forming +1 cations. Meanwhile, the elements in Group 17, known as the halogens, have seven electrons in their outermost shell and need to gain one electron to fill their shell and form −1 anions. The Group 1 and Group 17 elements form ionic bonds because they can easily transfer one electron from Group 1 to Group 17, thus achieving stable electronic configurations.