All the matter around us are made of tiny particles called atoms and molecules. While atoms of an element represent only one kind of particle, molecules are made of either the same or different kinds of one or more particles. This difference defines the two classes of compounds, namely heteroatomic and homoatomic molecules.
Definition: The heteroatomic molecules are made from different kinds of atoms, while the homoatomic molecules are made from a single type of atoms.
Homoatomic and Heteroatomic Molecules Questions with Solutions
Q1. The homoatomic molecule in the following is:
Explanation: The buckyball or C60 is made from only 1 kind of atom, namely carbon.
Q2. Give two examples of each of the homoatomic molecules and the heteroatomic molecules.
Answer: The examples of heteroatomic molecules are HCl and H2O. These compounds consist of two different kinds of atoms, i.e. hydrogen and chlorine, present in the HCl and hydrogen and oxygen in H2O.
Examples of homoatomic molecules are H2 and Cl2. The molecules in both elements are formed from a single type of atom, i.e. hydrogen and chlorine, respectively.
Q3. What are homoatomic molecules?
Answer: The homoatomic molecules are formed by only one kind of atom. This means that homoatomic molecules contain only a single type of nucleus. For example, O2, N2, S8, etc.
Q4. Is FeSO4 a heteroatomic molecule or a homoatomic molecule?
Answer: FeSO4 consists of 3 different types of atoms, namely iron, sulphur and oxygen. Since the molecule is not made up of only one kind of atom, FeSO4 is a heteroatomic molecule.
Q5. The mass of an atom of all elements is compared to:
a. The mass of a hydrogen atom
b. The mass of an oxygen atom
c. The mass of an atom of 12C
d. None of the above
Explanation: This is because the 12C isotope has an exact mass of 12 amu.
Q6. What is the difference between a heteroatom and a functional group?
Answer: Hydrocarbons are organic compounds made from carbon and hydrogen as their constituent elements. When any of the carbon or the hydrogen atom is replaced by an atom of a different element, that atom is called a heteroatom.
A functional group may be an atom or group of atoms which determine the properties of the hydrocarbons when a carbon or hydrogen atom is replaced by it.
Q7. Do the heteroatoms make a polar bond with the carbon atoms in the organic compounds?
Answer: Yes, this is because the carbon atoms have intermediate electronegativity. As a result, all the heteroatoms have either more or less electronegativity than the carbon atoms. Thus, when any heteroatom comes into contact with a carbon atom in an organic compound, the bond formed between them is polar. The polarity in the bonds arrives due to the difference in the electronegativities of the two different atoms.
Q8. The most stable form of phosphorus is:
a. White phosphorus
b. Red phosphorus
c. Black phosphorus
d. None of the above
Explanation: Black phosphorus is the most stable form of phosphorus at a given room temperature and pressure. Black phosphorus remains stable on heating up to a temperature of ~400-500 oC.
Q9. The smallest chemical entity that is capable of its own independent existence is:
d. None of the above
Explanation: Molecules are not the smallest chemical entity. On the other hand, ions are small but are not capable of their independent existence. Ions always exist in pairs, i.e. the positive and the negative ions making a neutral molecule. Atoms are the smallest chemical entities which are capable of their own independent existence.
Q10. Water is a _____ molecule.
Explanation: Water (H2O) is a triatomic molecule as it contains two atoms of hydrogen (2H) and one atom of oxygen (O).
Q11. What are functional groups?
Answer: Functional groups are specific sets of molecules that change the properties of the organic compounds attached to them. They are of different types. Functional groups are formed by a combination of specific atoms bonded together in a specific pattern by certain specific bonds.
Q12. State whether the given statement is true or false.
A molecule is a part of an atom.
Explanation: A molecule is a group of atoms made from either the same or different kinds of atoms. Hence, a molecule cannot be a part of an atom. In fact, atoms combine together to form molecules. Therefore, the given statement is false.
Q13. Do all heteroatoms form functional groups?
Answer: All functional groups are formed by the combination of heteroatoms. But not all heteroatoms form the functional groups.
Q14. How can a heteroatom be identified in an organic compound?
Answer: All organic compounds are formed from hydrocarbon chains and ringed structures. Any atom other than the hydrogen atom and the carbon atom is a heteroatom.
For example, nitrogen (N), sulphur (S), oxygen (O) and halogens (X) are heteroatoms.
Q15. NH3 is a:
c. Heteroatomic molecule
d. Homoatomic molecule
Explanation: NH3 is made from three types of atoms; thus, it is a heteroatomic molecule.
Practise Questions on Homoatomic and Heteroatomic Molecules
Q1. Define the heteroatomic and homoatomic polymers.
Q2. Choose the heteroatomic molecules from the given options.
d. All of the above
Q3. What is a polymer backbone?
Q4. How can we determine whether the given functional group is acidic or basic in nature?
Q5. What is the major difference between organic and inorganic polymers?
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