The formation of the NH2,ads amino species and its further reactions with hydrogen and NO on the unreconstructed Pt(100) surface were studied by means of high-resolution electron energy loss spectroscopy (HREELS) and temperature-programmed reaction (TPR) spectroscopy. The NH2,ads amino species forms during the reaction between H-ads and NO at 300 K. NH2,ads can be oxidized by NO at a temperature; higher than 260 K. The reaction at T greater than or equal to 300 K results in the evolution of N-2 and water. An essential amount of N-ads accumulates on the surface after the reaction at similar to 260 K and desorbs as a low-temperature TPR peak of N-2 at 320 K. TPR in a saturated coadsorption layer of NOads and NH2,ads prepared at 100 K shows an "explosive" behavior, manifesting itself in the evolution of narrow TPR peaks of N-2 and H2O at similar to 370 K. TPR in an unsaturated coadsorption layer of NOads and NH2,ads proceeds at a much lower temperature of <300 K, resulting in the "nonexplosive" desorption peaks of N-2 and H2O. The reaction between the NH2,ads and Hads species in the temperature range of 350-470 K results in ammonia evolution. At T < 400 K, NH3 forms through the addition of a hydrogen atom to NH2,ads and competes with the Hads recombination. At higher temperature, >400 K, the dissociation of NH2,ads serves as a source of hydrogen atoms for the NH2,ads hydrogenation, leading to the parallel evolution of ammonia along with N2 and H-2. The mechanism of the formation of NH2,ads species and its further reactions with NO and hydrogen on the Pt(100)-(1x1) surface are discussed in detail.