chapter 1 Organic Chemistry Dr. Rivas, CHAPTER 2: ACIDS AND BASES, Organic Chem Chapter 3, Ch 4

Which of the following statements correctly describe the conventions used when drawing a skeletal structure for an organic compound? (Select all that apply.)

-It is assumed that every carbon atom has enough hydrogens to make it tetravalent. -The unlabeled end of a line represents a C atom. -All heteroatoms are drawn and the hydrogens directly bonded to them.

In the structure shown, the formal charge on the C atom is equal to ____ and the formal charge on the O atom is equal to ____.

0, +1

Hydrogen

1 covalent bond, 0 nonbonding electron pairs

Iodine

1 covalent bond, 3 nonbonding electron pairs

Which of the following statements correctly describe the conventions used when drawing condensed structures in organic chemistry? (Select all that apply.)

Atoms are drawn next to the atoms to which they are bonded Lone pairs are omitted

Rank the following bonds in order of decreasing bond length, based on periodic trends, starting with the longest bond at the top of the list.

1. H-I 2. H-Se 3. H-Br 4.H-S

Arrange the steps involved in drawing a Lewis structure in the correct order.

1. count the valence electrons from all atoms, and place the atoms ext to each other according to their bonding patterns. 2. add an electron for each negative charge and subtract one for each positive charge. 3. place a bond between every pair of atoms and use the remaining electrons to fill octets with lone pairs. 4. form multiple bonds if all electrons have been used and any atom does not have an octet. 5. assign formal charges to all atoms

Correctly order the steps necessary to determine the geometry around a given atom. Place the first step at the top of the list and the last step at the bottom of the list.

1. draw a valid Lewis structure. 2. count groups around a given atom. 3. Match the number of groups with the associated geometry

electrons in the valance shell. By contrast, hydrogen, which is in the first row, will bond so as to attain a valence shell that contains_____ electrons.

8 and 2

Select all of the compounds that are constitutional isomers of chlorobutane (compound 1).

B,C

correctly describe the procedure for drawing a Lewis structure?

An electron is added to the total count for each negative charge on the species. For a neutral molecule the sum of the number of valence electrons for each atom gives the number of electrons used in the Lewis structure. A single bond, which represents 2 electrons, should be placed between every two adjacent atoms.

A 2p orbital, The 1s orbital, and The first shell can contain a maximum of how many electrons

2

Each orbital can have a maximum of how many electrons? Multiple choice question.

2

oxygen

2 covalent bonds, 2 nonbonding electron pairs

A covalent bond is a _____ electron bond that is formed through the _____ of electrons between two elements on the same side of the periodic table. Multiple choice question.

2, sharing

A covalent bond is a _____ electron bond that is formed through the _____ of electrons between two elements on the same side of the periodic table.

2, sharing. Covalent bonds form between two elements from the same side of the periodic table (e.g., H2, Cl2, CH4, and ICl are covalent molecules).

How many p orbitals are present in each shell from the second row onward?

3

What is the bonding pattern for oxygen when it has a formal charge of +1? Multiple choice question.

3 bonds and 1 lone pair

nitrogen

3 covalent bonds, 1 nonbonding electron pair

atom contains 7 valence electrons and 10 core electrons? Multiple choice question.

35, 17 Cl

There are _____ hydrogen atom(s) attached to Ca, _____ hydrogen atom(s) attached to Cb, and _____ hydrogen atom(s) attached to Cc in the structure shown.

3; 0; 1

What is the bonding pattern for nitrogen when it has a formal charge of +1?

4 bonds and no lone pairs

carbon

4 covalent bonds, 0 nonbonding electron pairs

With regard to formal charge, an oxygen atom with 1 lone pair and 3 bonds will "own" _____ of its valence electrons.

5

describe a chemical bond?

A chemical bond leads to increased stability. Atoms bond to attain a full outer shell of valence electrons.

Which of the following describe structures for which a second resonance structure can be drawn? (Select all that apply.)

A positively charged atom with an empty p orbital is located adjacent to an atom with a lone pair. A positively charged atom with an empty p orbital is located adjacent to a multiple bond. A lone pair is located on an atom directly attached to (adjacent to) a multiple bond

describe covalent bonding.

A single covalent bond comprises two shared electrons. Covalent bonds generally form between two elements from the same side of the periodic table.

which orbital goes with a or b

A- p orbital B- s orbital

correctly describe the general rule that governs chemical bonding?

An atom will seek to attain the electron configuration of the nearest noble gas. An atom will bond so as to attain a complete valence shell.

describe the general rule that governs chemical bonding?

An atom will seek to attain the electron configuration of the nearest noble gas. An atom will bond so as to attain a complete valence shell.

Match the geometry listed to the correct C atoms in the structure shown.

C of CH3 groups-- tetrahedral central C atom-- trigonal planar

In the skeletal structure for an organic compound, it is assumed that there is a _____ atom at the end of any line and at the junction of any two lines. This type of structure omits all ______ atoms except those directly bonded to a heteroatom.

Carbon and hydrogen

An ion with fewer electrons than its neutral form is a_____ and it has a _____ charge

Cation and positive

Match each type of ion with the correct charge. Cation Anion

Cation is positively Charges Anion is negatively charged

correctly describe covalent bonding.

Covalent bonds generally form between two elements from the same side of the periodic table. A single covalent bond comprises two shared electrons.

Which of the following statements correctly describes the basic principle of VSEPR theory?

Each group around a central atom is located as far from the others as possible.

Covalent bond

Electrons are shared between two nuclei.

ionic bond

Electrons are transferred and the resulting species attract one another.

steps that are used in the drawing of Lewis structures?

Form multiple bonds to an atom that does not have an octet. Assign formal charges to all atoms. Arrange atoms next to each other that you think are bonded together.

Rank the following bonds in order of increasing bond length (shortest to longest), based on periodic trends, starting with the shortest bond at the top of the list. Position 1 of 4 H-F correct toggle button unavailable H-F Position

H-F H-O H-Se H-S

correctly describe the normal bonding pattern for a neutral atom of each element.

Hydrogen forms 1 covalent bond and has no lone pairs. Oxygen forms 2 covalent bonds and has 2 lone pairs.

correctly describe isotopes?

Isotopes have different numbers of neutrons. Isotopes have different mass numbers.

Draw the Lewis structure of NH4+. Select all statements that correctly describe this Lewis structure.

Nitrogen makes four bonds in the Lewis structure. There are a total of 8 valence electrons in the Lewis structure

What does the group number of an element in the second row or above reveal about an element? Multiple choice question.

Number of valence electrons

Which of the following substances contain only covalent bonds? Multiple select question. KNO3 CaCl2 O2 CH3CH2CH3

O2 CH3CH2CH3

Which statements correctly describe the exceptions to the octet rule?

Phosphorous and sulfur can have more than 8 electrons around them. Hydrogen does not obey the octet rule. B and Be do not have sufficient valence electrons to form an octet in a neutral molecule.

Which of the following atoms are able to accommodate more than eight electrons in their normal bonding pattern (a neutral molecule)?

Phosphorus Sulfur

Which of the following structural features must remain the same when drawing resonance forms for a species?

Placement of single bonds Number of unpaired (single) electrons Placement of atoms

Which of the following statements correctly describe resonance structures? (Select all that apply.)

Resonance structures differ only in the arrangement of electrons. An individual resonance structure does not accurately represent the structure of a molecule or ion.

periodic table with the appropriate periodic trend. Same column Same row

Same column- similar electronic and chemical properties. same row- similar size.

Which of the following statements correctly describe the rules which must be observed when drawing resonance structures? (Select all that apply.)

The placement of atoms and sigma bonds always remains the same. Resonance forms must obey the normal rules of bonding. Resonance forms may differ in the number of multiple bonds present.

describe electron orbitals and shells?

The second shell contains three p orbitals. There is only one orbital in the first shell. The second shell can contain a maximum of 8 electrons.

Which of the following statements correctly describe how formal charge is assigned to an atom in a Lewis structure? (Select all that apply.)

The atom is considered to "own" half the shared electrons. Formal charge = (valence electrons) - (number of electrons owned) The number of shared electrons "owned" equals the number of bonds in the structure.

What is the approximate value of the bond angle A in the structure shown?

The central C atom in this structure is surrounded by 3 groups and will have a trigonal planar geometry with bond angles of approximately 120 degrees.

Which of the following statements correctly describe the components of a neutral atom? The electrons are located outside the nucleus of the atom. The nucleus comprises most of the volume of the atom. The charge on a neutron is equal but opposite to the charge on a proton. The nucleus contains positively charged protons. Neutral atoms contain equal numbers of protons and electrons.

The electrons are located outside the nucleus of the atom. The nucleus contains positively charged protons. Neutral atoms contain equal numbers of protons and electrons.

describe the components of a neutral atom?

The electrons are located outside the nucleus of the atom. Neutral atoms contain equal numbers of protons and electrons. The nucleus contains positively charged protons.

describe s and p orbitals?

The electrons in a p orbital are filled only after an s orbital in the same shell is filled. An s orbital is lower in energy than a p orbital of the same energy level.

Sodium chloride (NaCl) is an ionic compound. Which of the following statements correctly describe the bonding in NaCl?

The electrostatic attractive force between Na+ and Cl- ions defines the ionic bond in NaCl. Na loses an electron to form the cation Na+.

The general characteristics of orbitals?

The first shell contains only one orbital. An orbital is a region of space of high electron density. Each type of orbital has a unique shape and occupies a certain space.

describe the general characteristics of orbitals?

The first shell contains only one orbital. Each type of orbital has a unique shape and occupies a certain space. An orbital is a region of space of high electron density.

correctly reflect the formal charges on each of the elements in the structure shown?

The formal charge on nitrogen is -1. The formal charge on carbon is 0.

what is the mass number of an atom

The mass number is given by the sum of the protons and neutrons in the nucleus.

Which of the following statements correctly describe how to use curved arrows to illustrate electron pair movement?

The source of electrons may be a π bond. The tail of the arrow begins on an electron pair. The head of the arrow may end on an atom or a bond.

correctly describe electron orbitals and shells?

There is only one orbital in the first shell. The second shell can contain a maximum of 8 electrons. The second shell contains three p orbitals.

Which of the following options correctly describe the conventions used to represent a tetrahedral arrangement of atoms on a flat plane? Select all statements that apply

There will always be one dashed line and one wedged line in the drawing. Solid lines are used to represent any bonds in the plane of the page. Wedges and dashes are used to represent groups that are aligned one behind another. There will always be two solid lines showing bonds to the central atom.

True or false: A molecule with two or more resonance structures is said to be resonance stabilized.

True Reason: A molecule with two or more resonance structures is said to be resonance stabilized.

Which of the following contribute to the observed geometry around a given atom?

bond length bond angle

Which of the following arrows is used to separate two resonance structures?

a double headed arrow

16, 8 O

a group 6A element

electron

a negatively charged particle

proton

a positively charged particle found within the center of the atom

neutron

an uncharged particle that is located in the nucleus

An atom may lose or gain electrons to form an ion. If an ion has more electrons than its neutral form, it is called a____ and it has a ____ charge.

anion and negative

Isotopes are atoms of the same element that have the same _____ number but a different _____ number. This is because isotopes have the same number of protons but a different number of _____. Multiple choice question.

atomic, mass, neutrons

Resonance structures are Lewis structures that have the same placement of _____ but a different arrangement of _____.

atoms, electrons

A species containing a positively charged carbon atom is specifically called a(n) ______. Such a species is unstable because the positively charged carbon atom has ______ than an octet of electrons.

carbocation, less

Two compounds that have the same molecular formula but different connectivities of their atoms are called _____.

constitutional isomers isomers

23, 11 Na

contains 10 core electrons

12, 6 C

contains 4 valence electrons

31, 15P

contains 5 valence electrons

32, 16 P

contains 6 valence electrons and 10 core electrons

nucleus

contains almost all of the mass of the atom

Br2

covalent

A bond that results from the sharing of electrons is termed a(n) _______ bond, while a bond that involves the transfer of electrons is called a(n) _______ bond.

covalent and ionic

The existence of different resonance structures for a single compound is an indication that electrons are _____. This phenomenon causes the species to be _____ stable.

delocalized, more

Isomers are _____ molecule(s) that have _____ molecular formula(s).

different, the same

Atoms bond in order to achieve a full shell of _____ electrons, leading to a system that has _____ energy and increased stability, compared to the unbonded atoms.

valence; decreased

Each column in the periodic table is identified by a _____ number. Elements in the same column have similar _____.

group, electronic and chemical properties

The _____ number of an element for the second row and above reveals the number of _____ electrons.

group, valence

KCL

ionic

The atomic weight of an element is the weighted average of the mass of all the _____ of a particular element.

isotopes

Consider the molecule shown in the diagram. Each fluorine atom has three

lone pairs

The metal lithium _____ an electron to form the cation Li+, while the nonmetal bromine _____ an electron to form the anion Br-. The ions are held together by a strong _____ attraction in a crystal lattice.

loses, gains, electrostatic

With regard to determining formal charge, an atom with _____ lone pair(s) and _____ bond(s) "owns" a total of 4 valence electrons.

one; two zero; four

For every shell there are a certain number of subshells. The first shell has one orbital called a(n) _____ orbital. The second shell has two kinds of orbitals, _____. Each of these orbitals has a unique shape and occupies a defined space.

s; s and p

Which of the following structures is the correct Lewis structure for the molecule CH3Cl?

structure B

True or false: The Lewis structure of a neutral molecule includes the total number of valence electrons of all atoms in the molecule.

true

Lone pairs of electrons are also known as ______ electrons.

unshared nonbonding

The formal charge assigned to an atom is calculated by subtracting the number of electrons the atom "owns" from the total number of ______ electrons. The number of electrons "owned" by a specific atom is defined as being the sum of the ______ electrons and half the ______ electrons.

valence, unshared, shared Reason: The total number of valence electrons of a neutral atom is the same as the group number.