Download Democritus Early Greek philosopher who coined the term atom

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Transcript
Atoms, molecules,
elements and
compounds
Early Greek
philosopher
who coined
the term
atom.
It was in the early 1800s
that John Dalton, an
observer of weather and
discoverer of color
blindness among other
things, came up with his
atomic theory. Less than
twenty years earlier, in
the 1780's, Lavoisier
ushered in a new
chemical era by making
careful quantitative
measurements which
allowed the compositions
of compounds to be
determined with
accuracy. . .
Atoms are the smallest particle
of matter that retains all the
characteristics of the matter.
Electrons are the negatively
charged particles of atom.
Together, all of the
electrons of an atom create
a negative charge that
balances the positive
charge of the protons in the
atomic nucleus. Electrons
are extremely small
compared to all of the other
parts of the atom. The mass
of an electron is almost
1,000 times smaller than the
mass of a proton.

A proton is a subatomic
particle found in the nucleus
of all conventional atoms.
The only place you can find
matter without protons is in
a neutron star or the core of
powerful particle
accelerators. The proton has
a positive charge, which
balances out the negative
charge in atoms, electrons. If
an atom has an imbalance of
protons or neutrons, it is no
longer neutral and becomes
a charged particle, also
known as an ion.
Subatomic
particle that
has no charge.
A molecule is an
electrically neutral
group of two or more
atoms held together
by covalent chemical
bonds. Molecules are
distinguished from
ions by their lack of
electrical charge.
ELEMENTS
Elements are
substances
made of only
one type of
atom.
TWO OR MORE ELEMENTS CHEMICALLY COMBINED