Group 1: Alkali Metals
The elements in this group include Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr). These metals are all highly reactive, especially with water, and they tend to form +1 ions.
Group 2: Alkaline Earth Metals
The elements here are Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). These metals are less reactive than the alkali metals and commonly form +2 ions.
Group 7: Halogens
The halogens include Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At). These nonmetals are highly reactive and readily form compounds, usually gaining one electron to form -1 ions.
Group 8: Noble Gases
This group consists of Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn). They are characterized by having a complete valence shell and are largely inert, making them very unreactive.
Similarities Among Family Members:
Elements within the same group share similar chemical properties due to their similar electron configuration, particularly in their outermost shells. For example, alkali metals all have one electron in their outer shell, which explains their high reactivity and the tendency to lose that electron easily. Alkaline earth metals have two outer electrons, leading them to be less reactive than alkali metals but still form stable compounds. Halogens have seven outer electrons, making them eager to gain an electron to achieve a stable configuration. Noble gases have full outer shells, which is why they exhibit little to no reactivity. These similarities influence both the physical and chemical behavior of the elements within each group.