Which two groups of elements in the periodic table table are the most reactive?
1. halogens and noble gases
2. noble gases and alkali metals
3. alkaline earth metals and halogens
4. alkali metals and halogens
4. alkali metals and halogens
The two groups of elements in the periodic table that are the most reactive are alkali metals (Group 1) and halogens (Group 17). Therefore, the correct answer is option 4: alkali metals and halogens.
To determine which two groups of elements are the most reactive in the periodic table, we need to understand the general trends of reactivity among different groups.
Reactivity in elements is primarily determined by their electron configuration and the tendency to gain or lose electrons. Elements with fewer outer shell electrons generally have a higher reactivity because they have a stronger desire to gain electrons to complete their valence shell, or to lose the few electrons they have to achieve a stable electron configuration.
Based on this, the two groups that are the most reactive are alkali metals (Group 1) and halogens (Group 17 or Group 7A).
1. Halogens and noble gases: Noble gases are known for their stability and lack of reactivity because they have a full valence shell of electrons. On the other hand, halogens are highly reactive nonmetals that are one electron short of having a full valence shell.
2. Noble gases and alkali metals: Noble gases are chemically inert, meaning they are very unreactive due to their complete valence shells. Alkali metals, on the other hand, are the most reactive metals in the periodic table due to their single valence electron, which they readily lose to achieve a stable electron configuration.
3. Alkaline earth metals and halogens: Alkaline earth metals (Group 2) are less reactive than alkali metals but more reactive than most other elements. They have two valence electrons, which they can readily lose to achieve a stable electron configuration. Halogens, as mentioned earlier, are highly reactive due to their one electron short of a full valence shell.
4. Alkali metals and halogens: This is the correct answer. Alkali metals (Group 1) and halogens (Group 17) are the most reactive groups of elements in the periodic table. Alkali metals readily lose their single outer electron to achieve stability, while halogens readily gain one electron to complete their valence shell. This electron transfer leads to highly exothermic reactions and results in the formation of ionic compounds.