considering the shape of calcium nucleus like a sphere calculate the density of nucleus of calcium of mass number 40
Answers
You can calculate the mass (in grams) of a single Ca nucleus by dividing the mass number by Avogadro's constant if this is required. You also need a volume. You are assuming the Ca nucleus is a sphere so you can use the equation for calculating the volume of a sphere:
Volume of a sphere = 4/3 * pi * r^3
You therefore need to find the radius of a Ca atom. These can vary but will be approximately 195 pm.
It is up to you how you give the units for density. I would probably keep the volume in pico metres cubed (pm^3) to keep the number sensible. I may also avoid calculating the mass in grams of the Ca atom and just use the units: g mol^-1 pm^-3 for denisty. However, if the question has specified for 1 Ca atom then you will have to convert the mass number to grams to give you the units: g pm^-3.
Hope thats helped.