There are 118 elements on the periodic table
but sometimes it seems like just a handful get all the attention
We're always talking about carbon, oxygen, and hydrogen, and nitrogen
maybe with a little iron and calcium thrown in there if we're feeling extra generous
and sure we're all made mostly out of those elements and they're some
of the most common elements in the
universe, so it makes some sense that
they get top billing.
But there's a whole periodic table out there
there and we humans are great at finding
ways to use just about anything that
sticks around for long enough so here
are eight of the less famous elements
that you might not hear about all the
time but still play surprisingly
important roles in the technology all
around us
most people probably haven't even heard
of praseodymium but it's right there at
atomic number 59 with the symbol Pr
praseodymium is a lanthanide which means
you'll usually find it sitting in the
first row below the rest of the periodic
table this makes the table a little more
compact but there's also a good reason
that chemists put the lanthanides in
their own little section. They tend to
share a bunch of common properties since
the electrons around the lanthanides
can act pretty similarly from one
element to the next.
Lanthanides generally aren't great at conducting
electricity and they typically make
strong bonds with other elements which
brings us back to praseodymium it makes
strong heat-resistant bonds with other
metals so it's perfect for things like
aircraft engines which have to withstand
huge temperature swings without cracking
or breaking those heat-resistant bonds
are also one reason that glass made with
praseodymium is used in a lot of welder's
and glassblower's masks and goggles
they need to be able to see through that
glass without feeling the heat from what
they're working on. Lanthanides can also
make strong magnets and praseodymium is
no exception but if you're looking for a
powerful magnet you probably want to
check out one of praseodymium's
neighbors. Neodymium sits just to the
right of praseodymium. Its atomic number is
60 and like its neighbor neodymium is
also used to make heat-resistant glass
including the glass and tanning booth it
lets ultraviolet light through so that
you can get tanned but it blocks
infrared light so you don't feel too
warm but neodymium's main use is in
powerful magnet strong magnet needs two
things first
it needs atoms with lots of unpaired
electrons which make each atom into a
tiny individual magnet and second it
needs all of those atoms to line up with
each other to make one big magnet
neodymium isn't the lanthanide with the
most unpaired electrons but its atoms
are among the best and all staying alive
when neodymium is mixed with elements
like iron it can make some of the
strongest magnets on earth they're pretty
much everywhere from inside spinning
hard drives where the magnets are used to
read your data two MRIs where they can
scan your body. The connection between
electricity and magnetism allows us to
move a coil of wire within a magnetic
field to create electricity that's why
you'll find neodymium magnets and
microphones the sound waves from your
voice moving coil of wire next to a
magnet which produces an electric
current. It's also how most power plants
turn something like moving water into
electricity for home so really if
there's electricity running through
something
neodymium is probably involved somehow
light bulbs usually shine in a whole
range of colors but lasers are different
lasers use crystals whose atoms and
electrons are arranged so that if you
give them a bunch of energy they shine
and amplify light only a very specific
color and if you're looking for a laser
crystal you can't do much better than
YAGs: yttrium aluminum garnet. Yttrium is
one of four elements named after the
small village of Ytterby, Sweden where
seven elements have all been discovered
on their own yags are pretty strong and
heat-resistant but they don't really
give off any light but if you replace
about 1% of the yttrium with another
similar elements like erbium or
neodymium that's when things changed
dramatically "doped" YAGs as they're known
are some of the best laser crystals out
there and they can be just about any
color depending on the element that
replaced yttrium YAG lasers are the
ones doctors used for laser eye
surgeries and they were also probably
used to cut the components on your
computer's hard drive. So even if you've
never heard of them until just now
YAG lasers are the reason you can watch
this video in the first place so far
we've just talked about elements that
exist naturally on earth but americium
is different no matter how hard you try
you won't find natural americium
anywhere on the planet but there's
probably some americium in your house
right now like all the elements larger
than uranium americium is radioactive. It
decays into other elements over time by
shooting out different kinds of
particles every second for about 30
years a millionth of a gram of americium-241
sends out about a hundred thousand
alpha particles which are made up of two
protons and two neutrons so if you put a
detector nearby you'd be able to catch a
lot of those particles as they flew out
of the Americium atoms unless something
else got in the way which is how the
most common type of smoke detector knows
when to go off these smoke detectors
have about a microgram of americium near
detector and as long as nothing
in between them the detector keeps on
sensing particles coming out of the
americium, but once there's too much smoke in
the air or anything else really
it blocks those particles from getting
to the detector which sets off an alarm
some radioactivity can be dangerous but
the kind of smoke detector can also save
your life
Californinum is another radioactive
element that you won't find naturally
anywhere on earth. It decays by sending
out lots of neutrons which can
kick-start a chain of reactions used in
nuclear power plants that's not the only
place you'll find people using
californium it's also used before
companies extract oil. Before oil
companies drills somewhere they need to
know how much water there is in the
rocks and in the oil more water in the
oil the harder it is to get each barrel
of just the oil out of the ground so the
company's engineers use nuclear moisture
gauges which measure the water in the
rocks based on the way the water
reflects neutrons there's a small sample
of Californium in the gauge that sends
neutrons into the surrounding rocks the
gauge analyzes what gets bounced back
and uses that information to calculate
how much water is in the rock.By making
similar measurements engineers can also
test how dense the rocks are, giving them
an idea of how hard it will be to get to
the area on the first place and they
could do all of this with an element no
human has ever seen before nineteen
fifties speaking of dense rocks let's
talk about the densest element on the
entire periodic table: osmium
osmium's electrons all orbit especially close to
its nucleus so it's atoms compact closer
together than those of any other heavy
element it's so dense that engineers
actually don't really use it to build
very much
it's just too heavy to be worth it
especially when other metals are both
stronger and lighter but one place
osmium used to be very common was a
record player needle. Needles with osmium
didn't wear down from dragging along
records nearly as quickly as other
needles did. The strong close bonds that
osmium makes with other metals just
don't bend and break under that sort of
rubbing stress for the same reason
you'll probably find osmium in the tip
of a good fountain pen, just like record
player needles, fountain pens need to be
able to rub against different surfaces
for hundreds of hours without wearing
out or changing shape and super dense
super-hard osmium is perfect for that
job so if you're playing vinyl records
or using a fancy pen
there's probably some osmium involved
People have used antimony for thousands
of years all the way back to ancient
Egypt and Rome where they put it in
cosmetic products that's actually where
the strange-looking Sb comes from its
symbol on the periodic table the Latin
word that the Romans used for antimony
was "stibium," but today we mostly use
antimony for making flame-retardant
plastics. Fire is mostly a lot of carbon
atoms
bonding with oxygen in the air and
producing heat so a good flame retardant
stops those bonds from happening, and that's
exactly why antimony trioxide and
antimony atom bonded to three oxygens is
added to a lot of plastics. When it's
combined with other compounds that
contain elements like bromine or
chlorine it'll bond with oxygen in a
way that produces less heat stopping the
fire so antimony trioxide does its job
and stops fires but there is one big
drawback to using it on plastic. The hot
plastic tends to release a lot of smoke
that might be worse for you than the
burning plastic itself would have been
let's finish off with another element
from Ytterby: gadolinium. It's just four
elements over from our old friend
neodymium and it can make even stronger
magnets than neodymium does because
gadolinium has more of those unpaired
electron but its atoms get too
disorganized and stop pointing in the
same direction above about room
temperature above room temperature
gadolinium atoms just align with any
magnetic field they happen to be in that
makes them pretty useless for things
like fridge magnets and microphones but
they're great for MRI MRIs map out
what's going on in your body by
measuring how different regions respond
to the magnetic field generated by a big
moving magnet and no matter how much you
might feel like you're pulled toward the
frigid night
your body just isn't all that magnetic
so a lot of MRI patients are given a
small injection of a solution containing
gadolinium as the big magnet passes over
the gadolinium moves a lot in response to
the magnet which makes a much bigger
signal for the MRI to measure which
leads to much better map of whatever is
going on in there. So even the more
unusual elements in the periodic table
have their place in the technology
around  us whether they're keeping airplanes
working detecting smoke or being used in
medical scans these less popular
elements help power the world
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