Chemistry in a Nutshell
- The Atom
All macroscopic matter is made out of many tiny
particles called atoms. The study of how these atoms interact is
called Chemistry.
- Subatomic Particles
The three particles that make up atoms are protons,
neutrons, and electrons. Protons and neutrons are heavier than
electrons and reside in the "nucleus," which is the center of the
atom. Protons have a positive electrical charge, and neutrons have no
electrical charge. Electrons are extremely lightweight and are
negatively charged. They exist
in a cloud that surrounds the atom. The electron cloud has a radius 10,000
times greater than the nucleus.
- The Nucleus
The nucleus of an atom is made up of
protons and neutrons in a cluster. Virtually all the mass of
the atom resides in the nucleus. The nucleus is held together by the
tight pull of what is known to chemists and physicists as the "strong
force." This force between the protons and neutrons overcomes the
repulsive electrical force that would, according to the rules of
electricity, push the protons apart otherwise.
- Electrons
The electron is the lightweight particle that
"orbits" outside of the atomic nucleus. Chemical bonding is
essentially the interaction of electrons from one atom with the electrons of
another atom. The magnitude of the charge on an electron is equal to the
charge on a proton. Electrons surround the atom in pathways called
orbitals. The inner orbitals surrounding the atom are spherical but
the outer orbitals are much more complicated.
- Chemical Bonding
Chemically bonding occurs when two particles can
exchange or combine their outer electrons in such a way that is energetically
favorable. An energetically favorable state can be seen as
analogous to the way a dropped rock has a natural tendency to fall to
the floor. When two atoms are close to each other and their electrons are of
the correct type, it is more energetically favorable for them to come
together and share electrons (become "bonded") than it is for them
to exist as individual, separate atoms. When the bond occurs, the atoms
become a compound. Like the rock falling to the floor, they "fall"
together naturally.
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