1.
What is the Lewis structure for Water?
Correct Answer
A. A
Explanation
The Lewis structure for water is represented by the given option A. In this structure, the oxygen atom is in the center and is bonded to two hydrogen atoms. The oxygen atom has two lone pairs of electrons. This structure follows the octet rule, where each atom has a full valence shell with eight electrons. The Lewis structure accurately represents the bonding and electron arrangement in a water molecule.
2.
Lewis structure was introduced in which year?
Correct Answer
C. 1916
Explanation
The Lewis structure was introduced in 1916. This structure, developed by Gilbert N. Lewis, is a way to represent the arrangement of atoms and electrons in a molecule. It uses lines to represent chemical bonds between atoms and dots to represent valence electrons. The Lewis structure is a fundamental tool in chemistry for understanding and predicting the behavior of molecules.
3.
"Lewis dot formulas" is another name for Lewis structures.
Correct Answer
A. True
Explanation
The statement is true because "Lewis dot formulas" and "Lewis structures" are two different names used interchangeably to refer to the same concept in chemistry. Lewis structures are diagrams that represent the bonding between atoms in a molecule and the placement of electrons. The dots in the diagrams represent valence electrons, and they are named after Gilbert N. Lewis, who developed this notation. Therefore, "Lewis dot formulas" is indeed another name for Lewis structures.
4.
Lewis structure shows the bonding of atoms.
Correct Answer
A. True
Explanation
The Lewis structure is a diagram that represents the bonding of atoms in a molecule. It uses dots to represent valence electrons and lines to represent bonds between atoms. This diagram provides information about the arrangement of atoms and the sharing or transfer of electrons, which ultimately determines the chemical properties and behavior of the molecule. Therefore, the statement "Lewis structure shows the bonding of atoms" is true.
5.
What is the Lewis formula for ammonia (NH3)?
Correct Answer
A. A
Explanation
The Lewis formula for ammonia (NH3) is a representation of its molecular structure, showing the arrangement of atoms and their bonding. In this case, the Lewis formula A is the correct answer, as it correctly depicts ammonia as having one nitrogen atom bonded to three hydrogen atoms. The Lewis formula is a useful tool for visualizing the bonding patterns and electron distribution in molecules.
6.
Lewis structure was first founded by Robert Boyle.
Correct Answer
B. False
Explanation
The statement is false because the Lewis structure was actually first founded by Gilbert N. Lewis, not Robert Boyle. Lewis introduced the concept of electron dot structures in 1916, which are now commonly known as Lewis structures. These structures are used to represent the bonding and non-bonding electrons in a molecule or ion.
7.
In Lewis structure, _______ are used to represent shared pairs.
Correct Answer
B. Lines
Explanation
In Lewis structures, lines are used to represent shared pairs. This is because a line is a common convention used to represent a covalent bond, which is formed when two atoms share a pair of electrons. The line indicates that the two atoms are connected by a bond and are sharing electrons.
8.
What is the Lewis structure for Oxygen (O2)
Correct Answer
B. B
Explanation
The Lewis structure for Oxygen (O2) is represented by the option B. This is because Oxygen has 6 valence electrons, and in the Lewis structure, each Oxygen atom shares a double bond, resulting in a total of 4 shared electrons. The remaining 2 electrons are unshared, also known as lone pairs. Therefore, option B correctly shows the arrangement of the shared and unshared electrons in the Oxygen molecule.
9.
Which of the following has two bonding pairs and two unshared pairs of electrons?
Correct Answer
C. NH3
Explanation
In the Lewis structure of NH3 (ammonia), each hydrogen atom shares one electron with nitrogen, forming three covalent bonds. Nitrogen also has one unshared pair of electrons, resulting in a total of two bonding pairs and two unshared pairs around the nitrogen atom.
10.
What is the Lewis structure for SF2?
Correct Answer
B. B
Explanation
The Lewis structure for SF2 is shown in option B. In this structure, sulfur (S) is the central atom and is surrounded by two fluorine (F) atoms. Each fluorine atom forms a single bond with the sulfur atom, resulting in a linear molecular geometry. The Lewis structure accurately represents the arrangement of atoms and the bonding in SF2.