Which statement below is NOT true of sodium?

• A. Sodium is commonly found in nature as a free element.
• B. Sodium reacts vigorously with water to produce hydrogen gas.
• C. Sodium forms ionic compounds with nonmetals such as chlorine.
• D. Sodium is a soft, silvery metal that can be cut with a knife.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the properties of sodium as an element. Sodium is an alkali metal found in Group 1 of the periodic table, known for its high reactivity and characteristic physical and chemical properties.
2. Step 2: Analyze the statement 'Sodium is commonly found in nature as a free element.' Sodium is highly reactive and does not exist freely in nature; instead, it is found combined in compounds such as sodium chloride (table salt).
3. Step 3: Consider the statement 'Sodium reacts vigorously with water to produce hydrogen gas.' This is true because sodium reacts with water to form sodium hydroxide and hydrogen gas, a well-known chemical reaction.
4. Step 4: Evaluate the statement 'Sodium forms ionic compounds with nonmetals such as chlorine.' This is true since sodium readily loses one electron to form Na⁺ ions, which combine with Cl⁻ ions to form ionic compounds like NaCl.
5. Step 5: Review the statement 'Sodium is a soft, silvery metal that can be cut with a knife.' This is true as sodium is a soft metal with a shiny, silvery appearance and can be easily cut due to its low hardness.