Which groups on the periodic table are considered the most reactive?

• A. Group 1 (alkali metals) and Group 17 (halogens)
• B. Group 14 (carbon group) and Group 15 (nitrogen group)
• C. Group 2 (alkaline earth metals) and Group 18 (noble gases)
• D. Group 3 (transition metals) and Group 16 (chalcogens)

Answer: (A)

Verified step by step guidance

1. Understand that reactivity in the periodic table depends on how easily elements lose or gain electrons to achieve a stable electron configuration, often resembling the nearest noble gas.
2. Recognize that Group 1 elements (alkali metals) have a single electron in their outermost shell, which they tend to lose easily, making them highly reactive metals.
3. Know that Group 17 elements (halogens) have seven electrons in their outer shell and tend to gain one electron to complete their octet, making them highly reactive nonmetals.
4. Compare the reactivity of other groups: Group 14 and 15 have more stable electron configurations and are less reactive; Group 2 metals are reactive but less so than Group 1; Group 18 are noble gases and are very unreactive due to their full valence shells.
5. Conclude that the most reactive groups are Group 1 (alkali metals) and Group 17 (halogens) because of their strong tendency to lose or gain electrons, respectively.