Elements in Group 1 typically exhibit an oxidation state of +1, while those in Group 17 generally have an oxidation state of -1.

Group 1 elements, commonly referred to as alkali metals, include lithium ($\text{Li}$), sodium ($\text{Na}$), potassium ($\text{K}$), rubidium ($\text{Rb}$), cesium ($\text{Cs}$), and francium ($\text{Fr}$). These metals possess a single electron in their outermost electron shell, which they readily lose to achieve a stable electron configuration. This loss results in an oxidation state of +1. Alkali metals are known for their high reactivity, primarily due to this propensity to lose an electron, and they readily form ionic compounds when reacting with nonmetals.

Conversely, Group 17 elements, known as halogens, encompass fluorine ($\text{F}$), chlorine ($\text{Cl}$), bromine ($\text{Br}$), iodine ($\text{I}$), and astatine ($\text{At}$). Halogens contain seven electrons in their outermost shell and require one additional electron to attain a complete and stable electron configuration. Consequently, they tend to gain an electron during chemical reactions, resulting in a -1 oxidation state. Halogens are also highly reactive, particularly with alkali metals and alkaline earth metals, leading to the formation of various salts.

It is essential to recognize that while +1 and -1 are the most common oxidation states for Group 1 and Group 17 elements, respectively, these elements can exhibit different oxidation states under specific conditions. For instance, under extreme conditions, alkali metals may lose more than one electron, resulting in higher positive oxidation states. Similarly, halogens can display positive oxidation states when they form compounds with oxygen or other halogens.

Understanding the typical oxidation states of these elements is vital for predicting the products of chemical reactions and comprehending their properties. For example, the +1 oxidation state of alkali metals accounts for their pronounced reactivity and their inclination to form ionic compounds with nonmetals. Likewise, the -1 oxidation state of halogens elucidates their reactivity and their tendency to form salts with metals.