Module 03: Molecules and Compounds

Question 1

An atom’s valence electrons are located in the atom’s innermost energy level. (3 points)

1. True
2. False

Answer 1

False

Question 2

An atom has the following electron configuration.

1s²2s²2p⁶3s²3p⁴

How many valence electrons does this atom have? (4 points)

1. 2
2. 4
3. 6
4. 12

Answer 2

3. 6

Question 3

An atom’s Lewis dot structure has two dots. Which of the following elements could it be, and why? (4 points)

1. Calcium, because it is an alkaline earth metal with two inner shell electrons.
2. Carbon, because it has two electrons in its outermost p sublevel.
3. Lithium, because it is a group 1 element with two bonding electrons.
4. Magnesium, because it is a group 2 element with two valence electrons.

Answer 3

4. Magnesium, because it is a group 2 element with two valence electrons.

Question 4

The electron configuration of an element is 1s²2s²2p⁴. Describe what most likely happens when two atoms of this element move toward each other. (5 points)

Answer 4

This element (oxygen) has a total of 8 electrons, 2 in the innermost electron level, and 6 (out of 8) in the valence shell. Since it is on the relative right side of the periodic table, the element will not be as reactive; furthermore, since it needs 2 electrons to fill its valence shell, it is an anion (negative ion). If an identical element moves towards it, which also wants two electrons, the two elements likely react chemically and create a covalent bond, where they share 2 electrons to fill their valence shells. Therefore, the most likely result would be that the elements form a diatomic molecule, with covalent bonds, sharing two electron pairs.

Question 5

Valence electrons are involved in chemical bonding. (3 points)

1. True
2. False

Answer 5

1. True

Question 6

An atom’s Lewis dot structure has three dots. Which of the following elements could it be, and why? (4 points)

1. Aluminum, because it is in group 13 and has three valence electrons.
2. Lithium, because it is a group 1 element with three total electrons.
3. Magnesium, because it is in period 3 and has three valence electrons.
4. Potassium, because it is an alkali metal and has three inner shell electrons.

Answer 6

1. Aluminum, because it is in group 13 and has three valence electrons.

Question 7

The electron configuration of an element is 1s²2s²2p⁶3s¹. Describe what most likely happens when an atom of this element comes near an atom having seven valence electrons. (5 points)

Answer 7

The above atom has 11 total electrons, meaning that the first energy level has 2 electrons, the second 8 electrons, and the third 1 (valence) electron. Since there is one valence electron, this atom is in column one, meaning it is very reactive. For an atom to be stable (according to Lewis’s octet rule), the outermost energy shell requires 8 electrons. Therefore, if this element comes into contact with 7 valence electrons, it will give up the outer electron so that the original element only has 8 valence electrons. The other element has 8 as well. The elements will have an ionic bond because one gave away an electron to become a negative ion, and one gained an electron to become a positive ion.

Question 8

What type of ions do nonmetals naturally form? (3 points)

1. Negative ions, by gaining electrons to fill the valence shell
2. Negative ions, by losing electrons to empty the valence shell
3. Positive ions, by gaining electrons to fill the valence shell
4. Positive ions, by losing electrons to empty the valence shell

Answer 8

1. Negative ions, by gaining electrons to fill the valence shell

Question 9

What is the formula of the compound formed between chlorine (Cl) and calcium (Ca)? (3 points)

1. CaCl, because calcium loses one electron and chlorine gains one electron.
2. ClCa, because chlorine gains one electron and calcium loses one electron.
3. CaCl₂, because calcium loses two electrons and chlorine gains one electron.
4. ClCa₂, because chlorine gains one electron and calcium loses two electrons.

Answer 9

3. CaCl₂, because calcium loses two electrons and chlorine gains one electron.

Question 10

Which of the following is a correct formula unit of an ionic compound? (3 points)

1. Al₂O₃
2. Ca₂O
3. MgOH
4. NaCl₂

Answer 10

1. Al₂O₃

Question 11

What is the formula unit for a compound made from Pb4+ and oxygen? (3 points)

1. PbO₂
2. O₂Pb
3. Pb₄O₂
4. O₄Pb₂

Answer 11

1. PbO₂

Question 12

A student made the Lewis dot diagram of a compound as shown.

What is the error in the Lewis dot diagram? (3 points)

1. The number of dots around Cl should be six because it is receiving two electrons from Mg.
2. The number of dots around Mg should be one because there is only one Cl around Mg atom.
3. Another Cl should be shown around Mg that will transfer its unpaired electron to Mg.
4. Another Cl should be shown around Mg that will receive the second electron on Mg.

Answer 12

4. Another Cl should be shown around Mg that will receive the second electron on Mg.

Question 13

Potassium has a 1+ charge, and oxygen has a 2− charge. A Lewis dot diagram should contain two potassium atoms and one oxygen atom to show how these atoms form an ionic bond. (1 point)

True

False

Answer 13

True

Question 14

Define Chemical Bond:

Answer 14

Link between 2 atoms resulting in mutual attraction of nuclei for valence electrons

Question 15

Define Valence Electrons:

Answer 15

Electrons in outermost shell of atom → lost or shared with another atom

Question 16

What is Octet Rule (Specifically for group 01, 02, and 18)?

Answer 16

Gilbert Lewis

Electrons outer shell key chemical bonding

“Atoms of all elements have between 1- 8 valence electrons”

Group 01: 1 valence

• reactive
• transfer of electrons = chemical reaction

Group 02: 2 valence

Group 18: 8 valence

• must unreactive
• (according to Lewis) due to full outer shell

Question 17

What is the difference between a ionic bond and a covalent bond?

Answer 17

Ionic Bonds

Results from:

1. electrostatic attraction between + & - ions
2. Electrons given up by one elements to be gained by another

= atoms attracted

mostly metals

Covalent Bonds

Electrons shared between 2 atoms

• neither completely gaining/losing electrons
• Outer energy shells overlap

Nonmetals

Question 18

How does reactivity decrease/increase across the periodic table?

Answer 18

Decrease from left to right

Question 19

How do the valence electrons appear on:

1. Column 01
2. Column 02
3. Transition Metals
4. Colum 3-7
5. Colum 08

Answer 19

Column 01: 1 valence electron

Column 02: 2 valence electrons

Transition Metals:

columns not indicate valence electron

Go along group → increase of one electron

• left: reactive
• right: less reactive

Column 03 - 07: column = nom. valence electrons

Column 08:

• helium = 2 valence electrons
• others = 8 valence electrons

Question 20

How does valence electrons compare in the subshell s & p and d & f?

Answer 20

subshell s & p: often

d and f → harder to bond → rarly reactive

Question 21

What is Ionization Energy?

Answer 21

Ionization Energy: required to remove an electron (gas)

• remove highest energy electron
• left to right: increase
• top to bottom: decrease

Indicate how they react to change:

the difference in first energy = indicate type of bond form

Question 22

Define Electronegativity:

Answer 22

Electronegativity: (opposite) Measures tendency to attract electrons

• left to right: increase
• top to bottom: decrease

Elements similar E energy: Covalent

Similar E energy: Ionic

Question 23

What is Noble Gas Notation and what are the three steps?

Answer 23

Full atomic configurations = very long

• rather focus valence electrons
• abbreviated from = Noble Gas Notation

Step 01: Fist the last element (noble gas) from previous row

Step 02: use noble gas in shorthand; write in brackets

Step 03: Delete the noble gas full notation and only write the elements configuration from there.

Question 24

What are Cations, Neutral Atoms, and Anions?

Answer 24

Ionic Bond: transferral of 1+ electrons between atoms

• Cations (+) and anions (-) attract
• due to electrostatic forces

Cations

1. losses electron
2. more protons

Neutral Atoms

protons = electrons

Anions

1. gains electron
2. more negative

Question 25

How do metals and nonmetals compare in their electronegativity?

Answer 25

**Metals** positive charge = number valence electrons **Nonmetals** negative charge = number electron need fill valence shell

Question 26

Which two factors influence ionic bonds?

Answer 26

1. Electronegativity 2. Ionization energy

Question 27

How does electronegativity relate to ionic and covalent bonding?

Answer 27

**Ionic Bond**: difference in electronegativity of 1.7 - 4.0 **Covalent Bond**: difference of less than 1.7

Question 28

Define Ionization energy?

Answer 28

The energy required to remove an electron **Few electrons** → lose electrons generally metals **Almost full** → attract electrons generally nonmetals

Question 29

What are the steps to determine the Formula Unit?

Answer 29

*Chemical formula used to determine ionic compounds* Step 01: **Identify the charge of each ion** Step 02: **Write cation first + anion** (corresponds to most metals then nonmetals) Step 03: **determine the ratio of positive to negative ions needed to make the compound neutral** Crossing the charges method: * number of the charge of cation subscript of anion * visa versa Step 04: **Subscripts represent the lowest whole number ratio** Step 05: **Check to see if the net charge is zero**

Question 30

What are polyatomic Ions?

Answer 30

Polyatomic Ions: **atoms bond together in a covalent bond → overall +/- charge** Due to attraction to opposite charged ions → join with single-atom ions/polyatomic ions = ionic compound

Question 31

Explain the nature of non-metal covalent bonding:

Answer 31

**Nonmetals** → share electrons that overlap in half-filled orbitals from their valence shell * Gasses, liquids → _covalent_ * gives both a full outer shell * stable configuration of noble gasses * attracted to nucleus of other atoms * Double/Tripple Covalent Bonds: share 2/3 electrons * Form between atoms → similar electronegativity

Question 32

Define Diatomic molecules and the 7 types:

Answer 32

Diatomic Molecules: **_molecule 2 atoms of the same/different chemical element_** *7 diatomic molecules: (I Bought Clay For Our New House)* 1. Iodine 2. Bromine 3. Chlorine 4. Fluorine 5. Oxygen 6. Nitrogen 7. Hydrogen

Question 33

What is the difference between single, double, and triple covalent bonding?

Answer 33

**Single Bonds** * Covalent bond one pair of electrons are shared **Double Bonds** * Covalent bond two pairs of electrons shared **Triple Bonds** * Covalent bond three pairs are shared between _Incease in shared electrons → increase bong strength_

Question 34

What are the 4 steps to create a Lewis Dot Structure?

Answer 34

Step 01: **Count the number of valence electrons** Step 02: **Determine the amount needed to complete the octet rule** Step 03: **Place least electronegative element in the center of the molecule** except hydrogen Step 04: **Indicate shared electron** shared electron pair: H — H (line) Lines increase with amount of shared electrons: H = H

Question 35

What is the difference between Polar and Nonpolar Covalent Bonding?

Answer 35

**_Polar Covalent Bonds_** * Nonmetals **share electrons nonequally** * one higher electronegativity than other (_0.5 \< x - y \< 1.7_) * electrons spend more time near higher electronegative element Otherside: partially positive **_Nonpolar Covalent Bonds_** * Nonmetals share electrons equally * bonded atoms same elements * similar electronegavitity (_x-y \< 0.5_)

Question 36

How do ionic and covalent bonds compare when dissolving in water?

Answer 36

Ionic: Yes Covalent: Varies

Question 37

How do ionic and covalent bonds compare in the compound of consistency?

Answer 37

Ionic: Brittle Covalent: Soft

Question 38

Melting and boiling points of ionic and covalent bonds?

Answer 38

Ionic: high Covalent: low

Question 39

What is true of a covalent bond? (4 points) 1. It is the electrostatic attraction between oppositely charged particles. 2. It is the sharing of electrons by overlapping orbitals. 3. It involves the exchange of electrons from one atom to another. 4. It involves the sharing of neutrons between two nuclei.

Answer 39

**2.** It is the sharing of electrons by overlapping orbitals.

Question 40

A single covalent bond involves two atoms sharing one pair of electrons. (2 points) True or False

Answer 40

True

Question 41

The molecule CH2O contains two single bonds and one double bond. (2 points) True or False

Answer 41

True

Question 42

When two fluorine atoms bond together in F2, what type of covalent bond do they form? (4 points) 1. A double bond, because they overlap orbitals to share one pair of electrons. 2. A double bond, because they overlap orbitals to share two pairs of electrons. 3. A single bond, because they overlap orbitals to share one pair of electrons. 4. A single bond, because they overlap orbitals to share two pairs of electrons.

Answer 42

**3.** A single bond, because they overlap orbitals to share one pair of electrons.

Question 43

The table provides the number of valence electrons for each of the two atoms that form an ionic and a covalent compound. Composition of Compounds _Compound C_ 1. Atom 1 has seven 2. Atom 2 has two _Compound D_ 1. Atom 1 has six 2. Atom 2 has five Which of the following statements is true about one of the compounds? (4 points) 1. Compound C is ionic because both atoms are in need of electrons. 2. Compound D is covalent because both atoms are in need of electrons. 3. Compound D is ionic because one atom is in need of electrons and the other needs to lose electrons. 4. Compound C is covalent because one atom is in need of electrons and the other needs to lose electrons.

Answer 43

**2.** Compound D is covalent because both atoms are in need of electrons.

Question 44

An induced dipole occurs when one molecule with a permanent dipole repels another molecule's electrons, causing the electrons to be more concentrated on one end of the molecule than another. (4 points) True False

Answer 44

True

Question 45

What type of intermolecular force occurs between polar molecules? (4 points) 1. Dipole-dipole force 2. Hydrogen bonding 3. Induced dipole force 4. Polar covalent bonding

Answer 45

**1.** Dipole-dipole force

Question 46

What is the strongest intermolecular force that occurs between molecules of H2S? (4 points) 1. Covalent bonding 2. Dipole-dipole force 3. Hydrogen bonding 4. London dispersion force

Answer 46

2. Dipole-dipole force

Question 47

The electronegativity values of fluorine, oxygen, and hydrogen are compared in the table. Comparison of Electronegativity Fluorine: 4.0 Oxygen: 3.5 Hydrogen: 2.1 Which of the following statements is true about the strength of the hydrogen bonding in HF and H2O? (4 points) 1. HF ≥ H2O because δ− on O in the HO bond is greater than δ− on F in the HF bond. 2. HF \< H2O because the radius of H in HO is shorter than the radius of H in HF. 3. HF \< H2O because F in HF has an extra lone pair compared with O in H2O. 4. HF ≥ H2O because the HF bond is more polar than the HO bond.

Answer 47

**4.** HF ≥ H2O because the HF bond is more polar than the HO bond.

Question 48

An induced dipole occurs when a molecule's moving electrons are briefly more concentrated in one place than another, causing the molecule to become temporarily polarized. (4 points) True or False

Answer 48

False

Question 49

When comparing H₂, NH₃, O₂, and CH₄, which of the following statements is correct? (4 points) 1. CH₄ has the highest boiling point because it experiences dipole-dipole forces. 2. H₂ has the strongest intermolecular forces because it has the lowest mass. 3. NH₃ has the highest boiling point because it experiences hydrogen bonding. 4. O₂ has the strongest intermolecular force because it experiences London dispersion forces.

Answer 49

**3.** NH₃ has the highest boiling point because it experiences hydrogen bonding.

Question 50

Which statement is true for dipole-dipole forces? (4 points) 1. They are stronger than hydrogen bonding forces. 2. They are weaker than London dispersion forces. 3. They occur between ions and polar molecules. 4. They occur between polar molecules.

Answer 50

**4.** They occur between polar molecules.

Question 51

How does the electronegativity indicate the type of bonding?

Answer 51

**Covalent**: elements difference in electronegativity _\< 1.7_ **Ionic bond**: elements difference in electronegavitity _\> 1.7_

Question 52

What are the general trend in the periodic table regarding type of bonding?

Answer 52

nonmetals → covalently metals → ionically with nonmetals

Question 53

What are Binary Ionic Compounds?

Answer 53

1. compound composed of two different elements 2. bond due to _electrostatic attraction_ and _transferral or electrons_

Question 54

What are the two steps in naming binary ionic compounds?

Answer 54

Step 01: **Element form cation = first word in compound** Step 02: **negative ion named second** * shorten root word * add -ide end

Question 55

What is the Stock system to name metal ionic compounds?

Answer 55

Used for transition metals in the d block → multiple possible names for positive ions Stock system: use roman numeral after first element in compound to indicate the amount of change in the atom Roman numeral (I) → 1+ charge in first compound Roman numeral (II) → 2+ charge second compound .... In copper (I) oxide, the final ratio is 2:1. In copper (II) oxide, the ratio of 2:2 →1:1.

Question 56

What are the three steps to naming covalent compounds?

Answer 56

Step 01: **Add prefix to name the first element** * Represent the number of atoms of an element in bonds* * one atom in the first element: no prefix Step 02: **Add prefix to represent the number atoms second element** add to the root * add even if the second element has only one atom (mono) * Step 03: **Add the ending -ide to the last element**

Question 57

Sulfur dioxide is a covalent compound. (3 points) True False

Answer 57

True

Question 58

What is the correct name for CH₄? (3 points) 1. Carbon tetrahydride 2. Carbon (IV) hydride 3. Monocarbon tetrahydride 4. Monocarbon hydroxide

Answer 58

**1.** Carbon tetrahydride

Question 59

What is the correct name for FeCl₃? (3 points) 1. Iron (I) chloride 2. Iron (III) chloride 3. Iron trichloride 4. Iron chlorate

Answer 59

**2.** Iron (III) chloride

Question 60

What is the formula for potassium nitrate? (3 points) 1. KN 2. K₃N 3. KNO₂ 4. KNO₃

Answer 60

**4.** KNO₃

Question 61

Formula for Lithium perchlorate:

Answer 61

LiClO_⁴

Question 62

Formula for Lithium chlorite:

Answer 62

LiClO₂

Question 63

Formula for Lithium chloride

Answer 63

LiCl

Question 64

Pure carbon commonly occurs in two forms: strong diamonds and soft, brittle graphite. The graphite is much more brittle because its carbon atoms are held together by single bonds, compared to double bonds in diamonds. (2 points) True False

Answer 64

False

Question 65

What functional group consists of a carbon atom double-bonded to an oxygen atom? (3 points) 1. Carbohydrate group 2. Carbonyl group 3. Hydroxyl group 4. Ketone group

Answer 65

**2.** Carbonyl group

Question 66

CH₂OCH₂ is an organic compound with an oxygen atom bonded between the two carbon atoms, and it is not very soluble in water. What type of compound is this? (3 points) 1. Alcohol 2. Amine 3. Carbohydrate 4. Ether

Answer 66

**4.** Ether

Question 67

What organic compound it: Contains a nitrogen bonded to carbon(s) and is usually basic

Answer 67

Amine

Question 68

What organic compound it: Extremely long molecule chain with repeated molecular units

Answer 68

Polymer

Question 69

What type of organic compound is: Makes up cell walls, fats, or amino acids

Answer 69

Carbohydrate

Question 70

What type of organic compound is: Organic compound with an oxygen bonded between two carbons

Answer 70

Ether

Question 71

In a certain organic compound, one of the carbon atoms is bonded to four atoms. One of these is a carbon atom, and the other three are hydrogen atoms. What type of bond exists between the two carbon atoms? (3 points) 1. Ionic 2. Dispersion force 3. Double covalent 4. Single covalent

Answer 71

**4.** Single covalent

Question 72

A compound has the molecular formula C3H7OH. Which class of organic compounds does it belong to? (3 points) 1. Alcohols 2. Amines 3. Carbohydrates 4. Hydrocarbons

Answer 72

**1.** Alcohols

Question 73

The polarity of an oxygen-hydrogen bond is higher than the polarity of a nitrogen-hydrogen bond, allowing amines to be more soluble than alcohol. (2 points) True or False

Answer 73

False

Question 74

Carbon atoms naturally bond with each other in chains, rings, or networks, but they cannot bond with oxygen or nitrogen. (2 points) True False

Answer 74

False

Question 75

What functional group consists of a carbon atom double-bonded to an oxygen atom? (3 points) 1. Carbohydrate group 2. Carbonyl group 3. Hydroxyl group 4. Ketone group

Answer 75

**2.** Carbonyl group

Question 76

CH3CH2OH is an organic compound that is soluble in water. What type of compound is this? (3 points) 1. Alcohol 2. Amine 3. Ether 4. Hydrocarbon

Answer 76

**1.** Alcohol

Question 77

In a certain organic compound, one of the carbon atoms is bonded to four atoms. One of these is a carbon atom, and the other three are hydrogen atoms. What type of bond exists between the two carbon atoms? (3 points) 1. Ionic 2. Dispersion force 3. Double covalent 4. Single covalent

Answer 77

**4.** Single covalent

Question 78

A compound has the molecular formula C3H8. Which class of organic compounds does it belong to? (3 points) 1. Alcohols 2. Amines 3. Ethers 4. Hydrocarbons

Answer 78

**4.** Hydrocarbons

Question 79

Hydrocarbons, the carbonyl group, and carbohydrates all have carbon, and they only differ based on the type of carbon-carbon bonds that exist in the molecule. (2 points) True False

Answer 79

False

Question 80

Define the properties of carbon's electrons:

Answer 80

* 4 valence electrons * Strong tendency to make 4 bonds * Bonds: plates, networks, chains, rings * What: hydrogen, oxygen, nitrogen, sulfur, phosphorous

Question 81

What are the two types of pure carbon

Answer 81

1. Diamond 2. Graphine

Question 82

What are the properties of diamonds?

Answer 82

![]() Hardest known substance Solid: colorless & high density Bond: * single * three-dimensional tetrahedral No intermolecular forces (*is covalent)*

Question 83

What are the properties of graphine?

Answer 83

Looks: Soft solid, black Conductivity: good Arrangement: * layers of thin hexagonal "plates" * 1 double bond & 2 single bonds * trigonal planar shape Intermolecular forces: * weak London dispersion forces * soft and easily broken * * ![]()

Question 84

What is organic chemistry?

Answer 84

Study of carbon

Question 85

What are the functional groups of carbon (definition)?

Answer 85

Functional Groups: covalently bonded atoms within molecules responsible for chemical characteristics * unique molecular structures * undergo similar chemical reactions no matter what molecule it bonds with * Exception: functional group bonded to another functional graph*

Question 86

What are the types of Functional Groups? [7]

Answer 86

1. Hydrocarbons 2. Alcohols 3. Amines 4. Ethers 5. Carbonyl Groups 6. Carbohydrates 7. Polymers

Question 87

What are hydrocarbons?

Answer 87

![]() Contains only **carbon** and **hydrogen** Examples 1. Methane (CH4) * simplest * main component natural gas 2. Octane (C8H18) * component of gasoline Large diversity → of different type of bonding * chains or rings Bonding: * single, double, triple

Question 88

What are alcohols?

Answer 88

![]() **Hydroxyl group bonded with the carbon atom** Polarity in hydrogen-oxygen bonds → smaller alcohol compounds soluble in water * ex: ethanol (C2H5OH)

Question 89

Define "hydroxyl group:"

Answer 89

oxygen atom bonded with a hydrogen atom

Question 90

What are the Amine Groups?

Answer 90

![]() **Amine Groups: _Nitrogen atom bonded with 1,2,3 carbon(s)_** less soluble in water than alcohol lower polarity basic Ex: Alkaloids * in plants or marine organisms * medical effects Ex: caffeine

Question 91

What are "Ethers?"

Answer 91

![]() **_Oxygen_ atom bonded between _two carbon atoms_** * not soluble in water (*not form hydrogen bonds with oxygen)* * Little polarity * little attraction * bow boiling points

Question 92

What are Carbonyl Groups?

Answer 92

![]() **Carbon atom double-bonded to oxygen atom** Categories: * ketone, aldehyde, amide, carboxylic acid, or ester * Ex: Acetone (CH3COCH3) * nail polish remover

Question 93

What are _polymers_?

Answer 93

Repeated molecular units → monomers * very long (4-100 atoms) * too small to see with the eye Synthetic Polymers: * human-made plastic * variety of uses

Question 94

What are "Carbohydrates?"

Answer 94

![]() **Carbon, hydrogen, and oxygen atoms** * most abundant * forms more complex structures Empirical Formula: **CH2O** Ex: * cell walls of bacteria * exoskeletons of invertebrates * energy storage * makes up fats and amino acids

Question 95

An instantaneous dipole occurs when a molecule's moving electrons are briefly more concentrated in one place than another, causing the molecule to become temporarily polarized. (4 points) True False

Answer 95

True

Question 96

What is the strongest intermolecular force that occurs between molecules of CO2? (4 points) 1. Dipole-dipole 2. Induced dipoles 3. Ionic bonding 4. London dispersion

Answer 96

**4.** London dispersion

Question 97

The boiling points of diatomic halogens are compared in the table. ![]() Which of the following statements **best** explains the trends in boiling points? (4 points) 1. The atomic size increases down the group, and this decreases the strength of the intermolecular forces. 2. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces. 3. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces. 4. The chances of forming a permanent dipole increase down the group, and this increases the strength of the intermolecular forces.

Answer 97

**3.** The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.

Question 99

Define 'Chemical Bond:'

Answer 99

Link between 2 atoms resulting in mutual attraction of nuclei for valence electrons

Question 100

Define Valence Electron:

Answer 100

Electrons in outermost shell of atom → lost or shared with another atom

Question 101

What rule did Gibert Lewis come up with in 1916

Answer 101

**Octet Rule:** Electrons outer shell key chemical bonding **"Atoms of all elements have between 1- 8 valence electrons"** Group 01_: 1 valence_ * reactive * transfer of electrons = chemical reaction Group 02: _2 valence_ Group 18: _8 valence_ * must unreactive * (according to Lewis) due to full outer shell

Question 102

What are the two types of chemical bonding?

Answer 102

1. Ionic Bonding 2. Covalent Bonding

Question 103

What is Ionic Bonding?

Answer 103

1. electrostatic attraction between + & - ions 2. Electrons are given up by one element to be gained by another = atoms attracted mostly in *metals*

Question 104

What are covalent bonds?

Answer 104

Electrons _shared between 2 atoms_ * neither completely gaining/losing electrons * Outer energy shells overlap * Mostly nonmetals

Question 105

How does the outermost energy shell relate to electron configuration?

Answer 105

highest energy level electrons move between atoms & shared = chemical change

Question 106

What periodic trend is seen between reactivity and valence electrons?

Answer 106

Reactivity decreases from left to right Valence electrons increase from left to right

Question 107

How does columns convey the nature of an element's valence electrons?

Answer 107

_Column 01:_ 1 valence electron _Column 02_: 2 valence electrons _Transition Metals:_ * columns not indicate valence electron * Go along group → increase of one electron left: reactive right: less reactive _Column 03 - 07:_ column = nom. valence electrons _Column 08:_ * helium = 2 valence electrons * others = 8 valence electrons

Question 108

How does the type of subshell relate to valence electrons and reactivity?

Answer 108

Valence electrons: * subshell **s** & **p**: often * d and f → harder to bond → rarly reactive

Question 109

How does *ionization energy* compare to *electronegativity?*

Answer 109

***_Ionization Energy:_*** **requried to remove an electron (gas)** * remove highest energy electron * left to right: increase * top to bottom: decrease * Indicate how they react to change: * difference in first energy = indiate type of bond form **_Electronegativity_**: (opposite) **Measures tendency to attract electrons** * left to right: increase * top to bottom: decrease * Elements similar E energy: Covalent * Similar E energy: Ionic

Question 110

How does electronegativity relate to chemical bonding?

Answer 110

Elements similar E energy: **Covalent** Similar E energy: **Ionic**

Question 111

Neon is located in the last group of the periodic table. How many valence electrons does the element neon have? (4 points) 1. **1** 2. **2** 3. **4** 4. **8**

Answer 111

**4.** 8

Question 112

The table shows the total number of electrons in Atom A and Atom B. Which statement is correct? (4 points) 1. A will give up electrons to form bonds. 2. B will give up electrons to form bonds. 3. Both A and B will be chemically unreactive. 4. Both A and B will gain electrons to become stable

Answer 112

**3.** Both A and B will be chemically unreactive.

Question 113

What is the charge on an atom after it gains two electrons during the formation of a bond? (4 points) 1. One positive charge 2. Two positive charges 3. Two negative charges 4. One negative charge

Answer 113

**3.** Two negative charges

Question 114

What happens when the compound MgO is formed? (4 points) 1. Oxygen transfers two electrons to magnesium. 2. Oxygen receives two electrons from magnesium. 3. Magnesium forms an ion with −1 charge; oxygen forms an ion with +1 charge. 4. Magnesium forms an ion with +1 charge; oxygen forms an ion with −1 charge.

Answer 114

**2.** Oxygen receives two electrons from magnesium.

Question 115

# Define ionization energy. Describe how ionization energy impacts ionic bonding.

Answer 115

Ionization energy is the energy required to remove an electron from an atom, and on the periodic table, the trend is that ionization energy (similar to electronegativity) increases from left to right and increases from the bottom to the top. Ionization energy is very relevant in ionic bonding. For example, metals on the left side of the periodic table require less ionization energy than the nonmetals on the right to lose an electron, which is why metals are cation rather than anions because they are very willing to give up electrons. In contrast, noble gasses which already are in a "noble gas state" and do not need to lose or gain electrons to fill their valence electron shells, require immense ionization energy to remove electrons.

Question 116

What is the formula unit for a compound made from Li and Cl? (4 points) 1. LiCl because the total negative charge on Cl is one. 2. LiCl because the total negative charge on Li is two. 3. Li₂Cl because the total positive charge on Cl is one. 4. Li₂Cl because the total positive charge on Li is two.

Answer 116

**1.** LiCl because the total negative charge on Cl is one.

Question 117

The Lewis dot notation for two atoms is shown. What is represented by this notation? (4 points) 1. Mg gains two protons from O. 2. Mg donates two protons to O. 3. Mg gains two electrons from O. 4. Mg donates two electrons to O.

Answer 117

**4.** Mg donates two electrons to O.

Question 118

Which phrase best describes the bond in O2? (4 points) 1. Double covalent bond 2. Single covalent bond 3. Double ionic bond 4. Single ionic bond

Answer 118

**1.** Double covalent bond

Question 119

What best describes the bonding in a water molecule? (4 points) 1. An oxygen atom shares an electron pair with each H atom. 2. An oxygen atom shares a single electron with each H atom. 3. An oxygen atom receives an electron from each H atom. 4. An oxygen atom transfers an electron to each H atom.

Answer 119

**1.** An oxygen atom shares an electron pair with each H atom.

Question 120

What best explains the formula unit for a compound made from fluorine and hydrogen? (4 points) 1. HF, because fluorine is short of one electron, and hydrogen is in excess of one electron. 2. HF, because both fluorine and hydrogen are capable of forming only one covalent bond. 3. H2F, because fluorine is short of two electrons, and hydrogen is short of one electron. 4. H2F, because fluorine is capable of forming one, and hydrogen is capable of forming two covalent bonds.

Answer 120

**2.** HF, because both fluorine and hydrogen are capable of forming only one covalent bond.

Question 121

Look at this image. What do the lines in this image represent? (4 points) 1. Ionic bonds between carbon and oxygen 2. Non-bonded valence electrons of oxygen 3. Double covalent bonds in carbon dioxide 4. Valence electrons donated in carbon dioxide

Answer 121

**3.** Double covalent bonds in carbon dioxide

Question 122

What does the second word in the name of a binary ionic compound represent? (4 points) 1. The group 1 element 2. The negative ion 3. The positive ion 4. The metal

Answer 122

**2.** The negative ion

Question 123

What is the name of a compound having the formula CaCl2? (4 points) 1. Calcium chloride 2. Calcium dichloride 3. Calcium chlorate 4. Calcium perchlorate

Answer 123

**1.** Calcium chloride

Question 124

What does this image represent? (4 points) 1. Linear molecule with one domain 2. Linear molecule with two domains 3. Tetrahedral molecule with four domains 4. Trigonal planar molecule with three domains

Answer 124

**4.** Trigonal planar molecule with three domains

Question 125

Which of the following explains the VSEPR geometry of an ammonia molecule? (4 points) 1. It is tetrahedral because there are four bonded pairs around nitrogen. 2. It is trigonal pyramidal because there are four bonded pairs around nitrogen. 3. It is tetrahedral because there are three bonded pairs and one lone pair around nitrogen. 4. It is trigonal pyramidal because there are three bonded pairs and one lone pair around nitrogen.

Answer 125

**4.** It is trigonal pyramidal because there are three bonded pairs and one lone pair around nitrogen.

Question 126

Which of the following are electrostatic interactions of permanent dipoles in polar molecules? (4 points) 1. Ion-dipole forces 2. Hydrogen bonding 3. Dipole-dipole forces 4. London dispersion forces

Answer 126

**3.** Dipole-dipole forces

Question 127

The boiling point of chlorine is −34 °C. Which of the following best predicts the boiling point of iodine? (4 points) 1. Higher than −34 °C because dispersion forces are stronger in iodine due to a greater number of electrons. 2. Lower than −34 °C because chlorine is more polar than iodine on account of its higher electronegativity. 3. Higher than −34 °C because dipole-dipole interactions in iodine are stronger than dispersion forces in chlorine. 4. Lower than −34 °C because permanent dipoles created in chlorine are stronger than temporary dipoles in iodine

Answer 127

1. Higher than −34 °C because dispersion forces are stronger in iodine due to a greater number of electrons.

Question 128

What type of element is carbon? (4 points) 1. Chemically unreactive 2. Impure 3. Metal 4. Nonmetal

Answer 128

**4.** nonmetal

Question 129

What is organic chemistry? Name at least three categories of compounds that are studied as a part of organic chemistry. (8 points)

Answer 129

Organic chemistry is the study of carbon and its presence in the environment. There are different "functional groups under organic chemistry," which are groups of covalently bonded atoms with molecules responsible for chemical characteristics that make that molecular structure unique. There are 6 types of functional groups in organic chemistry, namely Hydrocarbons, Alcohols, Amines, Ethers, Polymers, Carbonyl Groups, and Carbohydrates. **Hydrocarbons** are compounds that contain both carbon and hydrogen atoms, such as methane. **Alcohols** are compounds that consist of the Hydroxyl group (an oxygen and hydrogen atom) bonded with carbon, which is quite soluble in water and has high polarity due to the hydrogen-oxygen bonding. **Amines** consist of a nitrogen atom bonded with up to three carbon atoms; they are less soluble and less polar than alcohol. **Ethers** consist of an oxygen atom between two carbon atoms, which are not soluble in water, have little polarity, and have a low boiling point.

Question 130

What does this image represent? (4 points) 1. Alcohol group 2. Carbonyl group 3. Ether group 4. Hydroxyl group

Answer 130

**1.** Alcohol group

Question 131

In an experiment, two unknown compounds (one an alcohol and the other an amine) of equal molecular mass were heated. The result of the experiment shows that Compound A boiled at a lower temperature than Compound B. Which of the following correctly explains the identity of Compound A and why this was the result? (4 points) 1. It is an amine; it contains nitrogen-hydrogen bonds that are less polar and oxygen-hydrogen bonds. 2. It is an alcohol; it contains nitrogen-hydrogen bonds that are less polar and oxygen-hydrogen bonds. 3. It is an alcohol; it contains oxygen-hydrogen bonds that are less polar and nitrogen-hydrogen bonds. 4. It is an amine; it contains oxygen-hydrogen bonds that are less polar and nitrogen-hydrogen bonds.

Answer 131

1. It is an amine; it contains nitrogen-hydrogen bonds that are less polar and oxygen-hydrogen bonds.

Question 132

Lithium is located in the first group of the periodic table. How many valence electrons does the element lithium have? (4 points) 1 2 4 8

Answer 132

1

Question 133

The electron configuration of an element is shown below. 1s²2s²2p⁶3s¹ Name the group this element belongs to in the periodic table and explain your answer. Based on the electron configuration, write one chemical property of this element. (8 points)

Answer 133

The element above has 11 electrons, 2 in the innermost energy-level, 8 in the middle energy-level, and 1 valence electron. The Octet Rule, posed by Gilbert Lewis in 1916, states that valence electrons are equal to their corresponding group on the periodic table (except transition metals, which has some variation). Therefore, according to the Octet Rule, this element is in Group 1 of the periodic table (Alkali Metals). The Alkali Metals are the most reactive elements on the periodic table, and since it has one valence electron, it will likely become a cation (a positive ion) by transferring the electron, in order to be in a stable state. Therefore, this element is very reactive and will likely not occure in its pure form in nature (because it requires little ionization energy to remove an electron).

Question 134

What is the charge on an atom after it gains two electrons during the formation of a bond? (4 points) 1. One positive charge 2. Two positive charges 3. Two negative charges 4. One negative charge

Answer 134

**3.** 1. Two positive charges 2. Two negative charges

Question 135

What happens when the compound NaCl is formed? (4 points) 1. Sodium transfers an electron to chlorine. 2. Sodium receives two electrons from chlorine. 3. Sodium forms an ion with −1 charge and chlorine forms an ion with +1 charge. 4. Sodium forms an ion with +2 charge and chlorine forms an ion with −2 charge.

Answer 135

**1. S**odium transfers an electron to chlorine.

Question 136

Which of these statements best describes the formula unit for a compound made from Mg and Cl? (4 points) 1. It is MgCl2 because the total negative charge on Cl is one. 2. It is Mg2Cl because the total negative charge on Mg is one. 3. It is MgCl2 because the total positive charge on Mg is two. 4. It is Mg2Cl because the total positive charge on Mg is two.

Answer 136

**3.** It is MgCl2 because the total positive charge on Mg is two.

Question 137

What is represented by this notation? (4 points) 1. Na loses one proton to Cl. 2. Na loses one electron to Cl. 3. Na gains two protons from Cl. 4. Na gains one electron from Cl.

Answer 137

**2.** Na loses one electron to Cl.

Question 138

Which phrase best describes the bond in H2? (4 points) 1. Double covalent bond 2. Single covalent bond 3. Double ionic bond 4. Single ionic bond

Answer 138

**2.** Single covalent bond

Question 139

What best describes the bonding in a carbon dioxide molecule? (4 points) 1. Carbon shares two of its electrons, and each oxygen shares four of its electrons. 2. Carbon shares four of its electrons, and each oxygen shares two of its electrons. 3. Carbon receives two electrons from each of the two oxygen atoms. 4. Carbon transfers two electrons to each of the two oxygen atoms.

Answer 139

**2.** Carbon shares four of its electrons, and each oxygen shares two of its electrons

Question 140

What best explains the formula unit for a compound made from nitrogen and hydrogen? (4 points) 1. NH₄, because nitrogen needs four electrons, and each hydrogen needs one electron. 2. NH₄, because nitrogen needs one electron, and each hydrogen needs four electrons. 3. NH₃, because nitrogen forms a single bond with each hydrogen atom. 4. NH₃, because nitrogen forms a triple bond with each hydrogen atom.

Answer 140

**3.** NH₃, because nitrogen forms a single bond with each hydrogen atom.

Question 141

What is the name of the compound CaS? (4 points) 1. Calcium sulfur 2. Calcium sulfide 3. Calcium sulfite 4. Calcium sulfate

Answer 141

**2.** Calcium sulfide

Question 142

What does this image represent? (4 points) H --- H 1. Linear molecule with one domain 2. Linear molecule with two domains 3. Tetrahedral molecule with four domains 4. Trigonal planar molecule with three domains

Answer 142

**1.** Linear molecule with one domain

Question 143

Which of the following explains the VSEPR geometry of a carbon tetrachloride molecule? (4 points) 1. It is bent because there are four bonded pairs around carbon. 2. It is tetrahedral because there are four bonded pairs around carbon. 3. It is bent because there are two bonded pairs and two lone pairs around carbon. 4. It is tetrahedral because there are two bonded pairs and two lone pairs around carbon.

Answer 143

**2.** It is tetrahedral because there are four bonded pairs around carbon.

Question 144

Which of the following are dipole-dipole interactions that occur only between molecules containing N-H, O-H or F-H bonds? (4 points) 1. Ion-dipole forces 2. Hydrogen bonding 3. Dipole-dipole forces 4. London dispersion forces

Answer 144

**2.** Hydrogen bonding

Question 145

The boiling point of bromine is 59 °C. Which of the following best predicts the boiling point of iodine monochloride, a polar compound? (4 points) 1. Higher than 59 °C because dipole-dipole interactions in iodine monochloride are stronger than dispersion forces in bromine. 2. Lower than 59 °C because ionic bonding in bromine is stronger than covalent bonding in iodine monochloride. 3. Lower than 59 °C because dipole-dipole interactions in iodine monochloride are weaker than in bromine. 4. Higher than 59 °C because ionic bonding in iodine monochloride is stronger than H-bonding in bromine.

Answer 145

**1.** 1. Higher than 59 °C because dipole-dipole interactions in iodine monochloride are stronger than dispersion forces in bromine.

Question 146

How many valence electrons does carbon have? (4 points) 1 2 4 8

Answer 146

4

Question 147

Explain what makes carbon so essential to the life on planet Earth. (8 points)

Answer 147

Carbon is the 17th most abundant element in the environment, and in air, water, rocks, fossil fuels, and life on earth (which are all carbon-based molecules). The atom's unique ability to bond in long chains, plates, networks, and rings makes it the base for multiple larger molecules. Since carbon has 4 valence electrons, it has a strong tendency to create 4 bonds with other atoms, which makes it so essential to life. Carbon can form 7 different types of functional groups (hydrocarbons, carbonyl groups, carbohydrates, alcohols, amines, polymers, and ethers), which makes it so relevant to life on earth. For example, amines (a nitrogen atom bonded with 1-3 carbon atom(s)) which is prevalent in marine organisms and plants. Carbohydrates, made up of carbon, hydrogen, and oxygen atoms, are the basis for most complex - living - structures, such as cell walls, exoskeletons, and amino acids.