Which material will feel coldest at room temperature? A. Plastic
B. Glass
C. Metal
O D. Rubber

option A

Explanation:

In general, metals feel colder or hotter to the touch than other materials at the same temperature because they're good thermal conductors. This means they easily transfer heat to colder objects or absorb heat from warmer objects. ... Polyethylene, a common plastic, has more than twice the heat capacity of most metals

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons