Answer: the rarest element is Francium. J is not on the periodic table. also Dmitri Mendeleev proposed the periodic table.
Explanation: Kinda looked the last one up.
Density =Mass/volume
When mass is constant, density is inversely proportional to volume or vice versa
When volume decreases, density increases
Hope it helps
The basic relationship between voltage, resistance and current of an electrical device is given by Ohm's law:

where
V is the voltage
I is the current
R is the resistance
The hot plate in our problem is connected to a source of V=120 V and it has a resistance of

, therefore we can rearrange the previous equation to calculate the current through the device: