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 nucleus of the helium atom contains 2 massive, positively charged particles. Thus, Z, the atomic number = 2. Z is simply the number of protons, massive, positively charged particles, present within the nucleus. Z thus defines the identity of the element: Z=1, hydrogen; Z=2, helium; Z=3, lithium;.....Z=80, mercury. You do not have to remember these numbers, because in every exam you ever sit you should be provided a copy of the Periodic Table, which lists all the elements in order of atomic number.