Which of the following elements is least metallic in nature?
Copper
Metallic nature refers to the tendency of losing electron. Based on the ease with which metal atoms lose electrons to form positively charged ions, the various metals are arranged in a series known as metal reactivity series and the metal whose atom loses electron most easily is placed at the top of the series while the one that ionizes least readily is placed at the bottom. As amongst the given substances copper is placed lowest, so copper is least metallic among given substances