Group 1 (Alkali Metals)
* High reactivity: Alkali metals have only one valence electron, which they readily lose to achieve a stable noble gas configuration. This makes them highly reactive.
* Reaction with oxygen: They react vigorously with oxygen in the air to form oxides, which are ionic compounds. For example, sodium reacts with oxygen to form sodium oxide (Na₂O).
* Reaction with water: They react violently with water, producing hydrogen gas and a hydroxide solution. This reaction is highly exothermic. For example, lithium reacts with water to form lithium hydroxide (LiOH) and hydrogen gas (H₂).
* Reaction with halogens: They react readily with halogens to form ionic halides. For example, sodium reacts with chlorine to form sodium chloride (NaCl).
Group 7 (Halogens)
* High electronegativity: Halogens have seven valence electrons and are highly electronegative, meaning they strongly attract electrons.
* Reaction with metals: They react with metals to form ionic halides. For example, chlorine reacts with sodium to form sodium chloride (NaCl).
* Reaction with non-metals: They can also react with other non-metals to form covalent compounds. For example, chlorine reacts with hydrogen to form hydrogen chloride (HCl).
* Diatomic molecules: Halogens exist as diatomic molecules (e.g., Cl₂, Br₂, I₂) due to their tendency to share electrons and achieve a stable octet.
In summary:
The high reactivity of Group 1 and Group 7 elements leads them to readily form compounds with other elements. This reactivity is driven by their desire to achieve a stable electron configuration, either by losing electrons (alkali metals) or gaining electrons (halogens).
