Answer 1:
Thank you for a great question! I will begin
with a quick review of what a chemical element
actually is. A chemical element is a pure
substance that is composed of only one type of
atom. Atoms are made of protons (positive
charge) and neutrons (no charge) in the center
(nucleus) surrounded by electrons (negative
charge). Each element is sorted by the number of
protons present. Ions are atoms with a
different number of electrons than protons.
Isotopes are atoms with a different number of
neutrons.
Now that we have that sorted, the short
answer to your question: No! We have
discovered all the elements that we think are
possible to exist based on the latest
experimental data. The problem comes when we
try to make these elements in a laboratory.
"As of November 2011, 118 elements have been
identified, the latest being ununseptium in
2010. Of the 118 known elements, only the first
98 are known to occur naturally on Earth; 80 of
them are stable, while the others are
radioactive, decaying into lighter elements over
various timescales from fractions of a second to
billions of years." Source:
chemical element
Most of the high-atomic number (atomic number
is the same as the number of protons) elements
are not very stable, and break down into lighter
elements that we know a lot about. We use this
fact to design and build nuclear power plants,
which harness energy stored in these
elements.
Just recently we have shown evidence for
elements 113, 114, 116, and 117. Here are a few
articles I found that talk about their
discovery:
elusive element
113
two new elements
new
element 117 discovered
To summarize:
1. We know which elements we are looking
for because anything with more than 118 protons
is highly unstable.(that is, it breaks down into
lighter elements right away)
2. There is still a lot of research
happening with isotopes and ions, even though
the atoms have already been discovered.
3. Even though we have discovered some
elements, there are plenty that have only
existed in a laboratory because they are not
naturally stable.
Thank you so much for your question! Please
share your knowledge with anyone who is
interested!
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