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
Atom (system on chip) 2011, Intel announced an accelerated roadmap for Atom SoC. The 22 nm Silvermont microarchitecture was scheduled for 2013 release, and release of the 14 nm Airmont microarchitecture was scheduled for 2014. It has been reported that Silvermont-based Atom SoCs will be codenamed Tangier (Merrifield smartphones), Valleyview (Bay Trail tablets), will be available in single-, dual- and quad-core versions, and Valleyview will include Intel's 7th generation GPU, allowing for 4–7× improvement over existing Atom GPUs. Other upcoming Silvermont-based Atom SoCs include Rangeley and Avoton (part of Edisonville platform). Airmont-based Atom platforms will be codenamed Moorefield (smartphones) and Cherry Trail (tablets) using