Video Transcript
The diagram shows the structure of
four different chemicals: a noble gas, a salt made from a metal and a nonmetal, a
metal, and a covalent compound. Which chemical is the covalent
compound? (A) Chemical P, (B) chemical Q, (C)
chemical R, or (D) chemical S.
One of the diagrams represents a
noble gas. Noble gases are found in the
rightmost group of the periodic table, group 18 or eight A. They have a full outer shell of
electrons; therefore, they are stable. As noble gases are stable, they
don’t need to form bonds to increase stability. Therefore, they are monatomic,
meaning that they exist as single unbonded atoms. Therefore, it is most likely that
chemical S is a noble gas.
One of the diagrams is a salt made
from a metal and a nonmetal. A salt is an ionic compound made of
cations, which have a positive charge, and anions, which have a negative charge. The only diagram which contains
positive and negative charges is chemical P. Thus, it’s likely that chemical P
represents a salt made from a metal and a nonmetal. The remaining diagrams represent a
metal and a covalent compound. A compound is a substance composed
of two or more types of atom or ion bonded together in a fixed ratio. As it’s a covalent compound, it
would be atoms that are bonded together.
The only remaining diagram which
depicts two different types of atom is chemical Q. Therefore, chemical Q must be the
covalent compound, and chemical R must be the metal. Therefore, chemical Q is the
covalent compound.
