Group I elements of modern periodic table are called — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

# Group I Elements Classification **Step 1: Identify Group I elements** Group I elements in the modern periodic table are: $Li$, $Na$, $K$, $Rb$, $Cs$, $Fr$ (excluding $H$). **Step 2: Examine their electronic configuration** All Group I elements have **one valence electron** in their outermost $s$-orbital: - General configuration: $ns^1$ (where $n$ = 2, 3, 4, 5, 6, 7) **Step 3: Determine their chemical behavior** - They readily **lose one electron** to form $M^+$ cations - They are highly **reactive metals** - They exhibit similar chemical properties **Step 4: Identify the group name** Group I elements are called **Alkali metals** (except hydrogen in older classifications). **Answer: A — Alkali Metals** These elements are soft, silvery metals with low ionization energies that react vigorously with water and oxygen, producing alkaline hydroxides ($MOH$), which is the origin of their name.