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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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Q
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Quantum_number
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INFOTEXT
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1992-09-02
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In physics, one of a set of four numbers that
uniquely characterize an electron and its
state in an atom. The principal quantum
number n (= 1, 2, 3, and so on) defines the
electron's main energy level. The orbital
quantum number l (= n - 1, n - 2, and so on
to l = 0) relates to angular momentum. The
magnetic quantum number m (= l, l - 1, l - 2,
and so on to 0 and then on to ... - (l - 2),
- (l - 1) and -l) describes the energies of
electrons in a magnetic field. The spin
quantum number ms (= + 1/2 or - 1/2) gives
the spin direction of the electron. The
principal quantum number, defining the
electron's energy level, corresponds to
shells (energy levels) also known by their
spectroscopic designations K, L, M, and so
on. The orbital quantum number gives rise to
a series of subshells designated s, p, d, f,
and so on, of slightly different energy
levels. The magnetic quantum number allows
further subdivision of the subshells (making
three subdivisions px, py, and pz in the p
subshell, for example, of the same energy
level). No two electrons in an atom can have
the same set of quantum numbers (the Pauli
exclusion principle).