Question

A metal, which melts on the palm:
A. Potassium
B. Sodium
C. Gallium
D. Zinc

Answer 1

Hint: Try to recall the physical state of all the elements given in the options. Melting on the palm means the metal is in the liquid state at human body temperature. Now, you can try to answer this question.

Complete step by step answer:
Let’s discuss each option one by one -

Option A, Potassium is a chemical element with the symbol K and atomic number 19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Here you can see it is soft but doesn't melt on the palm.

Option B, Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. The free metal does not occur in nature and must be prepared from compounds. It is also soft but doesn't melt on the palm.

Option C, The element gallium is an unexpected metal—it's a soft, silvery-white metal that is solid at room temperature (similar to aluminum) but it can literally melt in the palm of your hand. It's bizarre and a little unsettling to see, but it makes sense. The melting point for gallium (which is represented on the Periodic Table as Ga) is relatively low, at 29.8°C.

Option D, Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. It is slightly brittle but doesn't melt on the palm.

Therefore, we can conclude the correct answer to this question is option C.

Note: We should also know about some other properties of gallium. Gallium wets glass or porcelain and forms a brilliant mirror when it is painted on glass. It is widely used in doping semiconductors and producing solid-state devices such as transistors.