As of 2013, the United States spends about $554.2 billion annually to fund its military forces, and appropriates approximately $88.5 billion to fund Overseas Contingency Operations. Put together, the United States constitutes roughly 39 percent of the world's military expenditures.
the number of protons in the nucleus of an atom of a particular element. In a neutral atom, the atomic number equals the number of electrons. See also atom, electron, proton.
The atomic mass of an atom is usually within 0.1 u of the mass number. The number of protons an atom has defines what element it is. However, most elements in nature consist of atoms with different numbers of neutrons. An atom of an element with a certain number of neutrons is called an isotope.