Video Transcript
When comparing between cesium and
silicon at room temperature, which of the following is correct? (A) Cesium is dull, while silicon
is brittle. (B) Cesium is brittle, while
silicon is hard. (C) Cesium is a semiconductor of
heat, while silicon is a good conductor of heat. (D) Cesium is malleable, while
silicon is inductile. (E) Cesium is malleable, while
silicon is soft.
The question asks us to compare
cesium and silicon. Cesium is in group one of the
periodic table, and silicon, group 14. Silicon, sitting on this irregular,
stepped line, is a metalloid, while cesium on the left is a metal. Knowing this will help us identify
the properties of these two elements and therefore answer the question.
Here are some properties we can use
to distinguish between a metal and a metalloid or even a nonmetal. We can ask, is it lustrous? Or its opposite, is it dull? Is it ductile? Is the element malleable? And is it a good or poor conductor
of heat and electricity?
Cesium, being a metal, is
lustrous. We say a clean surface of cesium is
lustrous because it is able to reflect light evenly and efficiently without glitter
or sparkle. The metalloid silicon does have
some luster when its surface is cleaned. Cesium is pale gold, and silicon is
silver color. The metal cesium is ductile, which
means it can be pulled or drawn into long, thin wires. Although the metalloid silicon has
a lustrous nature like cesium, it is not ductile. It is inductile and cannot be drawn
into long thin wires. Like other metals, cesium is
malleable. It can be hammered into thin, flat
sheets. Silicon cannot do this. We say silicon is brittle; it will
crack or shatter when hammered.
Metals are excellent conductors of
heat and electricity, and cesium is no exception. Silicon is a good conductor of heat
but only a semiconductor of electricity. We have seen that silicon displays
some characteristics of metals and some of nonmetals, typical of a metalloid.
If we carefully examine the answer
options given, we will see that answer option (D) — cesium is malleable, while
silicon is inductile — is correct for both phrases. (A) is factually incorrect because
cesium is not dull; it is lustrous. (B) is incorrect because cesium is
not brittle; it is malleable and ductile. (C) is incorrect. Cesium is not a semiconductor of
heat but an excellent conductor of heat. We can also rule out answer option
(E). Although cesium is malleable,
silicon is not soft; it is hard. In fact, the name silicon comes
from a Latin word “silex,” meaning flint or hard stone.
Which of the following is correct
when comparing cesium and silicon at room temperature? The answer is (D) cesium is
malleable, while silicon is inductile.
