However it was in 1912 that the New Zealander Ernest
Rutherford gave us our modern
view of the atom when he showed that atoms have a positive nucleus surrounded at a relatively large
distance by the electrons, a picture that everyone today recognizes as the symbol for the atom.
The photograph shows Rutherford in his lab. The sign
says ‘Talk softly please’
supposedly put there because the detectors were sensitive to noise. However the more likely explanation is that
it was aimed at Rutherford by his
colleagues, since he was renowned for his booming voice.
Now it became clear what differentiates the elements -
the number of electrons and the
charge on the nucleus - for example hydrogen has one electron, helium has two, carbon six, lead eighty-two
etc.
However the story doesn’t stop there.