Concept explainers
Classify each of the following statements as true or false:
a) Molecular geometry around an atom may or may not be the same as electron-pair geometry around the atom.
b) Electron pair geometry is the direct effect of molecular geometry.
c) If the geometry of a molecule is linear, the molecule must have at least one double bond.
d) A molecule with a double bond cannot have trigonal pyramidal geometry around the double bonded atom.
e) A
f) A molecule is polar if it contains polar bonds.
g) A molecule with a central atom that has one lone pair of electrons is always polar.
h) A molecule with a central atom that has two lone pairs and two bonded pairs of electrons is always polar.
i) Carbon atoms normally form four bonds.
j) Hydrogen atoms never form double bonds.
(a)
Interpretation:
Whether the statement, “Molecular geometry around an atom may or may not be the same as electron-pair geometry around the atom” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “Molecular geometry around an atom may or may not be the same as electron-pair geometry around the atom” is true.
Explanation of Solution
The electron-pair geometry of any molecule can be decided on the basis of the number of electron pairs present around the central atom. Some electron pairs around the central metal atom are bonded and some are present as lone pairs. The electron-pair geometry is decided without considering the lone pairs. The molecular geometry is decided by considering the lone pairs. Therefore, if there is no lone pair present around a central atom, then the molecular geometry around an atom may be the same as electron-pair geometry. If there is lone pair present around the central atom, then molecular geometry around an atom may not be the same as electron-pair geometry. Therefore, the statement, “Molecular geometry around an atom may or may not be the same as electron-pair geometry around the atom” is true.
The statement, “Molecular geometry around an atom may or may not be the same as electron-pair geometry around the atom” is found to be true.
(b)
Interpretation:
Whether the statement, “Electron pair geometry is the direct effect of molecular geometry” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “Electron pair geometry is the direct effect of molecular geometry” is false.
Explanation of Solution
The electron-pair geometry is decided without considering the lone pairs. The molecular geometry is decided by considering both the lone pairs and the bond pairs. Therefore, electron pair geometry is not the direct effect of molecular geometry. Therefore, the statement, “Electron pair geometry is the direct effect of molecular geometry” is false.
The statement, “Electron pair geometry is the direct effect of molecular geometry” is found to be false.
(c)
Interpretation:
Whether the statement, “If the geometry of a molecule is linear, the molecule must have at least one double bond” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “If the geometry of a molecule is linear, the molecule must have at least one double bond” is false.
Explanation of Solution
If the geometry of a molecule is linear, the molecule must have two bond pairs around the central metal atom. There is no condition to have a double bond for linear molecule. The double bond is considered as electron density cloud. Therefore, the statement, “If the geometry of a molecule is linear, the molecule must have at least one double bond” is false.
The statement, “If the geometry of a molecule is linear, the molecule must have at least one double bond” is found to be false.
(d)
Interpretation:
Whether the statement, “A molecule with a double bond cannot have trigonal pyramidal geometry around the double bonded atom” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “A molecule with a double bond cannot have trigonal pyramidal geometry around the double bonded atom” is true.
Explanation of Solution
The trigonal pyramidal geometry is formed when a molecule have three bond pair and one lone pair. Ammonia
The statement, “A molecule with a double bond cannot have trigonal pyramidal geometry around the double bonded atom” is found to be true.
(e)
Interpretation:
Whether the statement, “A
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “A
Explanation of Solution
In
The statement, “A
(f)
Interpretation:
Whether the statement, “A molecule is polar if it contains polar bonds” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “A molecule is polar if it contains polar bonds” is false.
Explanation of Solution
Polar molecules are those molecules which have permanent dipole moment. Polarity depends on the symmetry of the molecule. In symmetric molecules, the net dipole moment is zero. This is because of cancellation of polar bonds in opposite directions. Therefore, symmetric molecules are nonpolar. Generally, asymmetric molecules are polar and symmetric molecules are nonpolar. Therefore, a molecule having polar bonds need not be polar. Therefore, the statement, “A molecule is polar if it contains polar bonds” is false.
The statement, “A molecule is polar if it contains polar bonds” is found to be false.
(g)
Interpretation:
Whether the statement, “A molecule with a central atom that has one lone pair of electrons is always polar” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “A molecule with a central atom that has one lone pair of electrons is always polar” is true.
Explanation of Solution
The lone pair present on the central atom distorts the symmetry of the molecule Therefore, the molecule becomes asymmetric. Asymmetric molecules are polar. So, molecule having lone pair on the central atom is polar in nature. Therefore, the statement, “A molecule with a central atom that has one lone pair of electrons is always polar” is true.
The statement, “A molecule with a central atom that has one lone pair of electrons is always polar” is found to be true.
(h)
Interpretation:
Whether the statement, “A molecule with a central atom that has two lone pair and two bonded pair of electrons is always polar” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “A molecule with a central atom that has two lone pair and two bonded pair of electrons is always polar” is true.
Explanation of Solution
The lone pair present on the central atom distorts the symmetry of the molecule Therefore, the molecule becomes asymmetric. Asymmetric molecules are polar. So, molecule having lone pair on the central atom is polar in nature. Therefore, the statement, “A molecule with a central atom that has two lone pair and two bonded pair of electrons is always polar” is true.
The statement, “A molecule with a central atom that has two lone pair and two bonded pair of electrons is always polar” is found to be true.
(i)
Interpretation:
Whether the statement, “Carbon atoms normally form four bonds” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “Carbon atoms normally form four bonds” is true.
Explanation of Solution
The valency of carbon is four. Tetravalency of the carbon is an important feature to form four stable bonds. Tetravalent carbon atom forms four bonds with other atoms. Therefore, the statement, “Carbon atoms normally form four bonds” is true.
The statement, “Carbon atoms normally form four bonds” is found to be true.
(j)
Interpretation:
Whether the statement, “Hydrogen atoms never form double bonds” is true or false is to be stated.
Concept introduction:
Molecular geometry is the
Answer to Problem 68E
The statement, “Hydrogen atoms never form double bonds” is true.
Explanation of Solution
The atomic number of hydrogen atom is one. Therefore, it has only one valence electron. Therefore, it can form only one bond with other atom. Therefore, the statement, “Hydrogen atoms never form double bonds” is true.
The statement, “Hydrogen atoms never form double bonds” is found to be true.
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Chapter 13 Solutions
Introductory Chemistry: An Active Learning Approach
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