Q. Consider the following:

1. Lithium
2. Potassium
3. Sodium

Which of the above is/are alkali metals?
Answer: 1, 2 and 3
Notes: 1. Lithium (Li) is the lightest metal and has atomic number 3. It is used in batteries and mood stabilizers. 2. Potassium (K) has atomic number 19 and is essential for biological functions, including nerve transmission. 3. Sodium (Na) has atomic number 11, is vital for fluid balance in the body, and is commonly found in table salt. All three elements are part of Group 1 in the periodic table, known as alkali metals, characterized by their high reactivity and formation of strong bases with water.