Rutherford and his assistants dealt with the following material: - A radioactive source of α particles (radium). These particles have positive electric charge. - A very thin gold foil (about 10-7 m thick). - A fluorescent detecting screen (zinc sulfide). nobody expected that 1 or 2 out of 10,000 particles rebounded against the gold foil.
Isotopes are atoms of the same element with different number of neutrons in their nuclei, so they have different mass numbers and different atomic masses.
ión es una partícula cargada eléctricamente constituida por un átomo o molécula que no es eléctricamente neutro.
Matter is made up of atoms. Atoms cannot be subdivided, destroyed or created. Atoms of a given element are identical in size, mass and properties. Atoms of different elements combine to form chemical compounds. In chemical reactions atoms are rearranged, not changed.