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.
In order to write an equation for a nuclear reaction, we must first establish some basic rules. Each of the elements involved in the reaction is identified by the chemical symbol. Two numbers are attached to the symbol. The number at the upper right is the mass number, also known as the A number. The 'A' number describes the atomic weight of the atom and identifies the number of protons and neutrons in the nucleus. The number at the lower left is the atomic number, or Z number. The 'Z' number describes the number of protons in the nucleus and determines the type of atom.