An atomic ion has 4 protons and 1 electron.
What is the charge of the ion?

Gravitational potential energy is given by the equation. PE=mgh, where m is an objects mass, g is the acceleration due to gravity, and h is the height of the object. The mass of the cat is 5 kg, g is 9.8 m/s^2, and the question asks for the potential energy relative to the floor, so the height is 1 meter.

PE=mgh
PE=5*9.8*1
PE=49 J