Video Transcript
In this video, we will learn about
the uses or applications of the metals in period four, specifically, the d block
metals of period four. We will investigate their common
uses as well as the industrially important compounds of these elements. First, let’s remind ourselves which
metals we are talking about.
On the periodic table, the period
four metals are potassium, calcium, scandium, titanium, vanadium, chromium,
manganese, iron, cobalt, nickel, copper, zinc, and gallium. Let’s focus on the period four d
block metals. These metals are collectively
called the first transition series, although technically zinc is not a transition
metal. A transition metal is an element
whose atoms have an incomplete d subshell, or which can give rise to cations with an
incomplete d subshell.
Now, why are we studying these
metals? Why are they so important? Did you know that most of these
metals are used by the human body? But why are they so important to
industry? Well, they are all money
makers. These metals are so useful in
specific applications that they generate a lot of money. For example, those used as
catalysts significantly speed up the rate at which chemical substances can be
produced. So, a manufacturer will make more
product in a shorter amount of time. In turn, profit is made
quicker. The elements used as catalysts or
in catalysts with other elements include scandium, titanium, vanadium, chromium,
manganese, iron, cobalt, nickel, copper, and zinc, all of them. Besides decreasing synthesis time,
these metals catalyze reactions which produce the base or starting materials for
many industrially important processes. Much money is generated because so
many reactions initially depend on these metal catalysts.
All of these metals are used in
alloys. Alloys have many uses in society
and are critical to the economy. Some of these metals are useful in
batteries. Worldwide, the trend is to find
alternative energy sources and energy storage systems. We don’t want to rely on fossil
fuels for energy. Batteries are a big part of
this. Manganese, cobalt, nickel, copper,
and zinc are all components of modern batteries. Iron, cobalt, and nickel are used
in magnets. We’ll see just now how important
magnets are in many, many devices. Many of these metals have
industrially important uses in compounds and as pure metals. Let’s look at some specific
examples of where these metals are used in catalysts, alloys, batteries, magnets,
compounds and as pure metals.
Vanadium is used in the V2O5
catalyst in the contact process which produces sulfuric acid. Iron is used as a pure metal in the
Haber–Bosch process, which generates gaseous ammonia. Iron is also used in the
Fischer–Tropsch process. In this process, liquid hydrocarbon
fuels are produced from carbon monoxide and hydrogen. And nickel is widely used in
hydrogenation reactions, for example, in the conversion of benzene to
cyclohexane. Now, let’s have a look at the use
of these elements in alloys.
The vast majority of alloys used
are based on iron, in other words, steel alloys. This is because not only do iron
alloys have useful properties such as strength, but iron is abundant in the Earth’s
crust. In fact, it’s the most abundant
metal of the first transition series. This is big business. Steels are covered in more depth in
another video. Scandium when alloyed with aluminum
results in a very hard lightweight alloy. Some MiG fighter jet components are
made using scandium aluminum alloys. Also used in aircraft as well as
aerospace components are the titanium alloys. They are low in density but very
strong. Vanadium and chromium, like
scandium, add hardness to alloys. They are used in high-strength
steels, for example, in cutting tools and in axles.
Copper and zinc are alloyed
together in brass. Brass is widely used for plumbing
components, for example, pipes and joints. Bronze is an alloy that uses copper
along with other metals like tin, aluminum, manganese, nickel, and zinc. Statues and medals are often made
from bronze. We can see that these period four
metals are highly useful when alloyed with other metals. They are perhaps more useful when
alloyed. But some of them are used in their
pure form, for example, copper. The vast majority of electrical
wires are made from copper. Zinc is used to galvanize more
reactive metals, for example, iron or steel. A thin layer of zinc is coated onto
the steel. This protects the steel from
exposure to oxygen and water vapor in the air, which would corrode it. Many steel structures can be
galvanized, for example, ladders, steel palisade fencing, and balustrades.
Chromium is also useful in its pure
form. A thin layer of chromium or
chromium alloy is electroplated onto a metal component to increase its corrosion
resistance, hardness, as well as to make it really shiny. Motorcycle parts are sometimes
chrome-plated as well as some fancy wheel rims or mags.
Let’s move on to the use of these
metals in batteries. Batteries or dry cells often
contain zinc and manganese dioxide. You may have heard of alkaline
batteries. These are conventional
batteries. Rechargeable batteries, however,
use nickel along with cadmium.
Now, what about magnets? Magnets are surprisingly widely
used not just for posting pictures on your refrigerator. Period four metals are used in
magnets for many devices, for example, in electric motors, transformers, generators,
scrap metal salvage yards, microwave ovens, TV display devices, radios, and much
more. Many magnets use iron in
conjunction with a coil. When electricity flows through the
coil, an electromagnet is produced. Iron is an integral part of
this. Try make your own electromagnet at
home. You’ll need an iron nail, copper
wire, and a battery, which could be a zinc and magnesium dioxide battery. Can you see that most of the
components of this system come from the first transition series?
But besides electromagnets, we’re
probably all more familiar with iron as a permanent magnet, while cobalt also forms
a permanent magnet along with samarium in samarium–cobalt magnets. These are powerful permanent
magnets used in high-temperature applications, for example, in aerospace components,
in generators, sensors, and some medical devices.
So far, we have seen the period
four metals used as catalysts, in alloys, in batteries, as pure metals, and in
magnets. The last category that we will look
at is the use in various compounds. There are many important compounds
containing these period four metals. For example, titanium in titanium
dioxide is used in sun block. The nanoparticles of titanium
dioxide absorb some wavelengths of UV light. Manganese is found in the
permanganate ion. This purple ion is a strong
oxidizing agent and is used in many applications, for example, in water treatment to
disinfect.
Chromium in the orange dichromate
ion is also used as an oxidizing agent, although it is not as strong an oxidizing
agent as permanganate. Dichromate as well as chromate ions
are used in pigments because of their strong color. Cobalt, specifically, the cobalt 60
isotope, is used in cancer treatment. In cobalt therapy, the gamma rays
from this radioactive isotope are directed towards tumors to kill them.
Let’s clear some space to look at a
few more examples. Here is another use for
chromium. Chromium in chrome alum and in
chromium sulfate is used to tan leather. Chromium cross-links the collagen
protein fibers in animal skins. In this way, the proteins in the
skins are stabilized, and the skins become more tough and leathery. And lastly, copper in copper
sulfate has some interesting uses. It acts as a herbicide,
bactericide, and fungicide to control the proliferation of algae, bacteria, fungi,
and even root growth in plants.
Now that we’ve learned about some
of the many uses of the period four d block metals, let’s practice.
Which of the following is one of
the applications of scandium? (A) Manufacturing of artificial
joints, (B) leather tanning, (C) manufacturing of MiG fighter jets, (D) metal
plating, or (E) manufacturing of car springs.
The question talks about the
element scandium or Sc. Scandium is found here on the
periodic table. Specifically, it is the first
element in the period four d block elements, in other words, the first element of
the first transition series. The first transition series metals
shown here are very useful metals. They are economically and socially
important. Now, the question asks about one of
the applications of scandium. When just a little bit of scandium
is added to aluminum, the resulting alloy, which is lightweight because of the
aluminum, becomes harder. The unique combination of being
lightweight and hard is perfect for use in aircraft.
Of the given answer options, the
application of scandium is the manufacturing of MiG fighter jets, or rather, some of
their components. Artificial joints are commonly made
from a variety of materials mixed together: ceramics, plastics, and metal. Titanium is the metal of choice in
artificial joints because it is lightweight and strong and shows no toxic effect
with human tissue.
Unlike some other metals, leather
tanning is achieved through the use of various compounds of chromium. The collagen proteins are
cross-linked by the chromium, and this stabilizes the leather, giving a durability
and a long life span.
Many metals can be used in plating,
but of the period four metals, chromium is the most common in this application. A thin layer of chromium is
electroplated onto other metal parts to create a hard, corrosion-resistant, and very
shiny surface. We call this chrome. You may have seen some
chrome-plated metal components on motorcycles.
Car springs are typically made of
steel. Steel is largely composed of iron,
along with some carbon. The combination of iron and carbon
and steel give a very strong alloy. Although very heavy, steel would
not be suitable to make MiG fighter jet components.
Of the answer options, the
application of scandium is manufacturing of MiG fighter jets or their
components.
Let’s summarize what we’ve learnt
about the period four metals. We learnt about some uses of the
period four d block metals, namely, scandium, titanium, vanadium, chromium,
manganese, iron, cobalt, nickel, copper, and zinc. We learned that these metals are
very important, if not critical, to society and the economy because they have so
many applications in daily life and industry and generate so much money. Their applications include use as
catalysts, for example, vanadium pentoxide in the contact process; use in many, many
alloys, for example, copper and zinc in brass; use as pure metals, for example,
copper in wires; use in batteries, for example, nickel in nickel–cadmium
rechargeable batteries; use in magnets, for example, cobalt in samarium–cobalt
magnets and iron in electromagnets; and lastly use in a variety of important
compounds, for example, manganese is used in the permanganate ion, which is used in
water treatment to disinfect.