Answer:
Transitional metals are good conductors of both heat and electricity.
But since there aren't any. It could be Calcium.
Because the mass is how much of something is in an object, gold and silver can have the same mass but have very different weights.
Hope I helped!
I don’t even know I’m just answering for pints
You can put a known amount sodium into some sort of time release mechanism such as a pill made from soluble material. Then you can place the sodium into a calorimeter with a known mass of water and record the temperature change the water undergoes during the reaction. Then you can use the equation q(water)=m(water)c(water)ΔT to find the amount of heat absorbed by the water. since the amount of heat absorbed by the water is the amount of heat released from the sodium, q(sodium)=-q(water). Than you can use the equation q(sodium)=m(sodium)c(sodium)ΔT and solve for c(sodium)
I hope this helps and feel free to ask about anything that was unclear in the comments.