Diameter of an atom from density

[ombudsmansect]

Homework Statement

1 The density of copper is 8930 kg m-3, its mass number is 63.55 and its atomic number is 29.
a) Calculate the mass of a copper atom in kg.
b) How may electrons and protons does a copper atom have?
c) Estimate the diameter of a copper atom from this data.

Homework Equations

(4/3)(pi)r^3

The Attempt at a Solution

Just need to confirm that when calculating the mass in part a) i can just use its mass number or should i add up the individual mass of nucleons. i know that this will eb more than the atomic mass here but does that energy have weight or not? I am uncertain as to wether energy formed from mass has weight or what.

The main issue though is part c) i just figure that i will use the weight from a) to find a volume using the density and hence calculate the diameter tho this is rather crude, any other way of doing this i don't know about? all help greatly appreciated thanks guys :D

 

[ehild]

Just need to confirm that when calculating the mass in part a) i can just use its mass number

Yes, you can.

The main issue though is part c) i just figure that i will use the weight from a) to find a volume using the density and hence calculate the diameter

It is not weight but mass, but the method you outlined should be all right.

ehild