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The most abundant element on our In a solid, the bonds locking the
planet (meaning in the Earth’s substance together are strong,
crust) is oxygen (about 46% of the however in a liquid the bonds are
earth’s crust mass), followed by weaker. In a gas, the molecules
silicon (28%). There are small are bound together very weakly
amounts of aluminum (8%), iron and can move about easily (and
(5%), potassium (2%), and even bump into each other).
magnesium (2%).
A gas becomes a plasma when the
You and I are mostly made up of molecules
six elements: oxygen (65%), move about so
carbon (18%), hydrogen (10%), rapidly that
nitrogen (3%), calcium (1%) and they knock
phosphorous (1%). Less than 1.5% electrons off
of the human body is made up of the atoms
other stuff (sulfur, sodium, copper, when they
iron, lead, arsenic…) collide. Plasmas are made up of
electrons and ions moving about
There are two elements that are a
o
liquid at room temperature (25 C): with high amounts of energy.
You’ve seen plasma in neon signs,
bromine (Br), a reddish-brown
lightening, fluorescent lights,
liquid that turns both toxic and
plasma globes, and stars.
corrosive when in vapor form; and
mercury (Hg), a toxic silvery metal Atoms can be
liquid used in old-fashioned linked up
thermometers. together to
form
States of Matter Ordinary matter
molecules. For
exists in one of four states: solid,
example, a
liquid, gas, and plasma. Which
covalent bond between two atoms
state an atom (or molecule or ion)
share an electron (there’s a
is in depends on how much energy
covalent bond between the oxygen
it has and how much freedom the
and each hydrogen in a water
particles have to move around.
molecule – both atoms share the
Substances can move between electrons).
states by losing or gaining heat
Ions and molecules can be
energy. For example, you can melt
chemically linked together using
an ice cube (solid) in the sun
the electrostatic force to form
(adding energy) into a liquid and
crystals. For example, table salt
eventually into water vapor.
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