atoms

• what is the radius of the atom and nucleus?

  -atom have a radius of 0.1 nanometres, this is 1x10-10m(standard form)

  -nucleus has a radius of 1x10-14m(this is around 1/10000 of the radius of an atom)

  -whole mass of atom is concentrated in the nucleus
• what is the relative mass and charge of proton, neutron and electron?

  proton=1 and +1

  neutron=1 and 0

  electron=0 (1/1840)and -1
• why are atoms neutral?

  Equal number of protons and electrons, that have the same charge but opposite signs so they cancel each other out (+ & -)
• -protons= atomic number

  -protons and neutrons= mass number

  -neutrons=mass number - atomic number