Procedure 1: Differentiate Metals and Non-metals
- Metals: Characterized by luster, high thermal and electrical conductivity, and malleability (exemplified by sodium and iron).
- Non-metals: Typically exhibit a dull appearance, low conductivity, and brittleness (illustrated by carbon in its allotropic forms, graphite and diamond).
Procedure 2: Evaluate Each Element
- Sodium (Na): Located in Group 1, possesses a shiny surface, and exhibits conductivity. Classified as a metal.
- Iron (Fe): A transition metal, known for its strength and conductivity. Classified as a metal.
- Carbon (C): Situated in Group 14, its allotropes include graphite (dull, exhibits moderate conductivity) and diamond (an electrical insulator). Classified as a non-metal.
- Copper (Cu): A transition metal, notable for its shininess and superior electrical conductivity. Classified as a metal.
Procedure 3: Final Determination
Carbon is identified as the sole non-metal among the provided options, corresponding to selection (3).