The hydrogen atom shows the simplest arrangement. Consisting of an electron and a proton (commonly called nuclei). Electrons as carriers of electric charges is called the smallest elementary charge.
Electrons are elementary negative charge carriers, protons are elementary positive charge carrier.
Figure 1.8 Figure atom schemes:
a) a hydrogen atom
b) carbon atoms
Electron negative elementary charge equal to the positive elementary charge of the proton. Therefore charges atom has exactly the same effect. Atom is electrically neutral.
Neutral atom consists of a positive charge as much with a negative charge.
Eg carbon atom has 6 electrons and 6 protons. In addition to proton nuclei also contain parts that are electrically neutral, which is commonly called the neutron. Protons and neutrons determine the actual atomic weight. Atom else altogether 103 pieces with a similar arrangement. Distribution of electrons in the electron trajectories based on certain rules. But the number of electrons remains always the same as the number of protons.
Ion
Atom loses an electron, and thus the atoms have more positive charge than negative charge. Intact atoms positively charged, carry out an electrical reaction, which was to draw negative charge. Atoms plus / was given an electron, then the whole he is negatively charged and attract positive charge. Such charged atoms on the contrary it can also attract different charges, means that the atoms move. On this basis, the atom, is called ion (ions = running, bhs, Greece).
Positively or negatively charged atom or group of atoms called ions.
Figure 1.9 Schematic formation of ion
Can be concluded that :
Excess electrons produces a negative charge, a shortage of electrons produces a positive charge.