Question

Which of the following metals can be easily cut with a knife ?

• A. Na
• B. Cu
• C. Ni
• D. Al

Hint:

Remember that the alkali metals (Group 1), such as Lithium (Li), Sodium (Na), and Potassium (K), are exceptionally soft metals. This is a key distinguishing physical property.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks to identify a metal that is soft enough to be cut with a standard knife. This property is characteristic of a specific group of metals in the periodic table.

Step 2: Detailed Explanation:
\[\begin{array}{rl} \bullet & \text{Na (Sodium): Sodium is an alkali metal (Group 1). Alkali metals are known for being very soft and having low densities. Sodium is soft enough to be easily cut with a knife, revealing a shiny surface that quickly tarnishes in air. } \\ \bullet & \text{Cu (Copper), Ni (Nickel), Al (Aluminum): These are transition and post-transition metals. They are much harder and stronger than alkali metals and cannot be cut with a simple knife. They possess typical metallic properties like high tensile strength and hardness. } \\ \end{array}\]

Step 3: Final Answer:
Sodium (Na) can be easily cut with a knife.