Atom to the positively charged nucleus by the attraction created from opposite electric charges. If an atom has more or fewer electrons than its atomic number, then it becomes respectively negatively or positively charged as a whole; a charged atom is called an ion. Electrons have been known since the late 19th century, mostly thanks to J.J. Thomson; see history of subatomic physics for details. Protons have a positive charge and a mass 1,836 times that of the electron, at . The number of protons in an atom is called its atomic number. Ernest Rutherford (1919) observed that nitrogen under alpha-particle
Ariel Atom ones. In 2005 "Track and Race Car" magazine published the results of a comprehensive test of a range of cars, from the Porsche 911 Carrera S, Ford GT, BMW M5 to the Caterham CSR 260. The supercharged Ariel Atom 2 won the 0–161–0 km/h (0–100–0 mph) test by a clear margin at 10.88 seconds, ahead of the Caterham CSR 260 (11.41) and the Ford GT in fourth (13.17). The following year, the Atom won "Autocar"s 0–100 mph challenge as the new Ariel Atom 2 300 bhp supercharged edition achieved a time of 6.86 seconds, and then stopped from 100 in