Video Transcript
Copper is a transition metal, while
sodium is an alkali metal. Which of the following tests would
yield similar results for these metals? (A) Testing if they are
electrically conductive. (B) Storing them in dry air. (C) Placing them in cold water. (D) Heating them to 100 degrees
Celsius. Or (E) using a hammer to change
their shape.
Alkali metals and transition metals
have some similarities in their properties and many differences. Let’s take a look at how copper and
sodium are similar and different depending on the situation.
When stored in dry air, sodium will
react with atmospheric oxygen and quickly tarnish. This is because sodium metal is
easily oxidized. Copper, however, oxidizes quite
slowly as with many transition metals. Some transition metals, like gold,
will only oxidize in very specific conditions. And so we know that answer choice
(B) can’t be the correct answer because these results would be very different.
When alkali metals, such as sodium,
are placed in cold water, they react very vigorously and violently and can even
cause dangerous explosions. Copper, on the other hand, is
essentially nonreactive with water and definitely does not react violently or
explode. So we can eliminate answer choice
(C).
Next, alkali metals tend to have
low melting and boiling points, while transition metals have incredibly high melting
and boiling points. For example, sodium has a melting
point under 100 degrees Celsius. So, at above 100 degrees, it’ll be
in a liquid state at standard pressures. And so we can eliminate answer
choice (D).
Looking at answer choice (E), we
know that transition metals are hard and strong and do not readily change shape. When hit with a hammer, we usually
need to strike a transition metal with a lot of force and multiple times if we
wanted to change its shape. You might even envision a
blacksmith working to make a sword. Alkali metals, however, are much
softer and more malleable. They tend to change shape more
readily when affected by mechanical force. And so, we can eliminate answer
choice (E).
And this leaves us with answer
choice (A). Both transition metals and alkali
metals tend to be good conductors of electricity because there’s little resistance
for electrons to pass through these elements, giving them similar electronic
properties.
And with that, we should be able to
revisit and answer the question. Copper is a transition metal, while
sodium is an alkali metal. Which of the following tests would
yield similar results for these metals? And the correct answer is answer
choice (A), testing if they are electrically conductive.
