1.
When two or more atoms bond together they form a
Correct Answer
B. Molecule
Explanation
When two or more atoms bond together, they form a molecule. A molecule is a group of atoms that are held together by chemical bonds. In a molecule, the atoms can be of the same element or different elements. This bonding allows the atoms to share electrons and create a stable structure. Therefore, the correct answer is molecule.
2.
All molecules are made up of
Correct Answer
B. Atoms
Explanation
Molecules are composed of atoms. Atoms are the basic building blocks of matter and combine together to form molecules. Therefore, all molecules are made up of atoms.
3.
Molecules can be easily separated.
Correct Answer
B. False
Explanation
Molecules are chemically bonded making them very difficult to separate. Only highly trained scientists with special equipment can separate molecules.
4.
Why do atoms bind together to form molecules?
Correct Answer
B. To fill their valence electron shell and become a more stable substance
Explanation
Atoms bind together to form molecules in order to fill their valence electron shell and become a more stable substance. The valence electron shell is the outermost shell of an atom, and when it is filled, the atom becomes more stable because it has achieved a full complement of electrons. By bonding with other atoms, atoms can share, gain, or lose electrons to achieve this stable electron configuration. This bonding allows atoms to form more complex structures and create a wide variety of substances with different properties.
5.
Which of the following is an example of a substance that is composed of molecules?
Correct Answer
B. Carbon Dioxide (CO2)
Explanation
Carbon Dioxide (CO2) is an example of a substance that is composed of molecules. Molecules are formed when two or more atoms chemically bond together. In the case of carbon dioxide, one carbon atom is bonded to two oxygen atoms, forming a molecule. Sodium and gold, on the other hand, are elements that exist as individual atoms and not as molecules.
6.
Molecules join together by
Correct Answer
A. Sharing electrons
Explanation
Molecules join together by sharing electrons. This is because electrons are negatively charged particles that orbit around the nucleus of an atom. When atoms come close to each other, their outermost electrons can interact and be shared between the atoms, creating a chemical bond. This sharing of electrons allows atoms to achieve a more stable electron configuration, resulting in the formation of a molecule. Sharing protons or neutrons is not a common way for molecules to join together. Therefore, the correct answer is sharing electrons.
7.
A molecule has different properties from the elements from which is was made.
Correct Answer
A. True
Explanation
When elements combine to form a molecule, they undergo a chemical reaction which results in the formation of a new substance with different properties than the individual elements. This is because the arrangement and bonding of atoms in a molecule leads to the emergence of new chemical and physical properties. Therefore, it is true that a molecule has different properties from the elements from which it was made.
8.
Molecules are held together by what kind(s) of bonding?
Correct Answer
D. Both A and B
Explanation
Molecules are held together by both ionic bonding and covalent bonding. Ionic bonding occurs when there is a transfer of electrons between atoms, resulting in the formation of ions that are attracted to each other. Covalent bonding occurs when atoms share electrons, creating a strong bond between them. Both types of bonding contribute to the stability and structure of molecules. Metallic bonding, on the other hand, is not involved in holding molecules together, but rather is responsible for the bonding within metals.
9.
 
 
What is the name of this molecule?
Correct Answer
B. Water (H2O)
Explanation
The correct answer is Water (H2O) because water is a molecule composed of two hydrogen atoms bonded to one oxygen atom. The molecular formula for water is H2O, indicating the presence of two hydrogen atoms and one oxygen atom in each molecule. Hydroxide (OH) is a polyatomic ion consisting of one oxygen atom and one hydrogen atom, but it is not the name of this specific molecule. Oxygen (O2) and hydrogen (H2) are both elements, not molecules, and do not accurately describe the composition of this molecule. "Both C and D" is an incorrect option as it combines two elements (carbon and hydrogen) that are not present in this molecule.
10.
Which of these is a true statement?
Correct Answer
A. Molecules are always moving
Explanation
Molecules are always moving because they possess kinetic energy. This movement is due to the constant motion of the atoms within the molecule. Even at extremely low temperatures, molecules still exhibit some level of movement, although it may be reduced. Therefore, it can be concluded that molecules are always in motion.