The correct option is (d) 11 (2,8,1). An element with atomic number 11 is sodium. It belongs to Group 1 and forms a basic oxide, sodium oxide (Na₂O), which reacts with water to form strong alkali sodium hydroxide.
Science important questions Final Exam 2025 Class 10
Science Question Paper class 10
The correct answer is (d) 11 (2,8,1). The element with atomic number 11 is sodium, with electronic configuration 2,8,1. It belongs to Group 1 (alkali metals). Metals generally form basic oxides. Thus, sodium forms sodium oxide (Na₂O), a strongly basic oxide, which reacts with water to produce sodium hydroxide, confirming its metallic and basic nature.