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
Captain Atom not mentioned in the panel in which they appear, but the Captain Atom is visually similar to Charlton's original version of the character. However, according to comments by Grant Morrison, this alternate universe is not the pre-Crisis Earth-4. 2007's "" features Captains Atom from alternate universes. The combatants of the series are introduced as a new Breach of Earth-8, a Ronnie Raymond/Nathaniel Adam fusion called "Quantum-Storm" from Earth-37, and another from Earth-38 who rules over his Atomic Knights. Additionally, issue #1 introduces a "Brigadier Atom" from Earth-13 married to Nightshade, and in "Countdown: Arena" #3, Breach gathers together a group