Which group of elements has oxidation numbers of +1, +2, and +3 respectively?

The group of elements that has oxidation numbers of +1, +2, and +3 respectively corresponds to Groups 1, 2, and 3 of the periodic table.

Group 1 elements, which include the alkali metals like lithium (Li), sodium (Na), and potassium (K), commonly exhibit an oxidation number of +1. This occurs because they tend to lose one electron to achieve a stable electron configuration, often resembling that of noble gases.

Group 2 elements, known as the alkaline earth metals, such as magnesium (Mg) and calcium (Ca), typically have an oxidation number of +2. These elements usually lose two electrons when forming compounds, again striving for stability.

Group 3 includes elements like aluminum (Al) and gallium (Ga), which can exhibit an oxidation state of +3. These elements often lose three electrons, particularly in their most stable forms in various compounds.

Together, the oxidation states of +1, +2, and +3 represent a clear trend among these specified groups, making this grouping of elements distinctive in their ability to adopt these oxidation states.