Answer:
Ionic Bonds
Step-by-step explanation:
Ionic bonds are bonds formed by the transfer of electrons.
Groups 1A and 7A
As denoted by the "A" in the group name, both 1A and 7A are main group families. Main group families have known characteristics and, often, unique names. Elements from group 1A are known as alkali metals. Elements from group 7A are known as halogens. Elements from group 1A and most of the right side of the periodic table are metals. Elements from group 7A and most of the left side of the periodic table are nonmetals.
Valence Electrons
One of the known characteristics of groups 1A and 7A is the number of valence electrons. Valence electrons are the electrons on the outermost shell of an atom.
Alkali metals have 1 valence electron and halogens have 7 valence electrons. Note that the fewer valence electrons an atom has, the easier it is to remove valence electrons and vice versa. This is due to a property known as electronegativity. Electronegativity is how much an atom will pull electrons toward itself. The more valence electrons an atom has, the higher the electronegativity.
Ionic Bonding
Since alkali metals only have 1 valence electron, when they bond with other elements, they tend to lose an electron. On the other hand, halogens have 7 valence electrons, so they tend to gain an electron when they bond. Thus, if a group 1A element bonds with a group 7A, the alkali metal will give an electron to the halogen.
This transfer of electrons forms an ionic bond. Almost all bonds between metals and non-metals are ionic.