The Atom and Atomic Structure
An
atom is the smallest building block of matter. Atoms are made of neutrons,
protons and electrons. The nucleus of an atom is extremely small in comparison
to the atom.
Most
of the atom is just empty space. The rest of the atom consists of a positively
charged nucleus of protons and neutrons that are surrounded by a cloud of
negatively charged electrons. The nucleus is the center of the atom. An atom is
an extremely small particle of matter that retains its identity during chemical
reactions. During the latter nineteenth century a series of experiments showed
that atoms are comprised of smaller particles. An atom consists of a nucleus and
one or more electrons surrounding the nucleus. The nucleus, the core of the
atom, has the majority of the mass of the atom and a positive charge. An
electron is a very light particle which circles the nucleus. It has a negative
charge.
In
an electrically neutral atom, the number of electrons equals the positive charge
on the nucleus. The nucleus of the atom is composed of smaller particles called
neutrons and protons. A proton has a positive charge equal in magnitude to the
negative charge of an electron. This means that in an electrically neutral atom,
the postive of charge the protons, combined with the negative charge of the
electrons, would result in no charge because they would cancel each other out. A
proton's mass, however, is a whopping 1836 times that of the electron. A
neutron, however, has a mass almost identical to a proton's, but it has no
electrical charge associated with it.
Molecules and Ions