Ch 1,2,3- Atomic Structure, Periodic Table, Bonds

Question 1

“Each proton has an amount of charge equal to

Answer 1

“the fundamental unit of charge (e = 1.6 × 10−19 C)”

Question 2

“Atomic mass is nearly synonymous with mass number. Atomic weight is

Answer 2

a weighted average of naturally occurring isotopes of that element.”

Question 3

In E=R/-n^2 is E proportional to N?

Answer 3

Yes

At first glance, it may not be clear that the energy (E) is directly proportional to the principal quantum number (n) in Equation 1.3. Take notice of the negative sign, which causes the values to approach zero from a more negative value as n increases (thereby increasing the energy). Negative signs are as important as a variable’s location in a fraction when it comes to determining proportionality

Question 4

“the state of lowest energy, in which all electrons are in the lowest possible orbitals”

Answer 4

Ground State

Question 5

“In general, an atom is in an _______ state when at least one electron has moved to a subshell of higher than normal energy.”

Answer 5

Excited

Question 6

In E=-R/n^2 the negative sign in the equation accounts for absorption and emission. Thus, a ______ E corresponds to emission, and a ______ E corresponds to absorption.”

Answer 6

Positive, Negative

Question 7

“we now understand that electrons move rapidly and are localized within regions of space around the nucleus called”

Answer 7

orbitals

Question 8

What principle is this? “It is impossible to simultaneously determine, with perfect accuracy, the momentum and the position of an electron”

Answer 8

Heisenberg Uncertainty Principle

Question 9

“according to _____________ , no two electrons in a given atom can possess the same set of four quantum numbers.”

Answer 9

the Pauli exclusion principle, no two electrons in a given atom can possess the same set of four quantum numbers.”

Question 10

How to find the number of electrons within a shell?

Answer 10

2n^2

Question 11

“The first quantum number is commonly known as ________ and is denoted by the letter n”

Answer 11

the principle quantum number

“This is the quantum number used in Bohr’s model that can theoretically take on any positive integer value. The larger the integer value of n, the higher the energy level and radius of the electron’s shell.”

Question 12

“The difference in energy between two shells _______ as the distance from the nucleus increases”

Answer 12

Decreases.

“For example, the energy difference between the n = 3 and the n = 4 shells is less than the energy difference between the n = 1 and the n=2

“Remember, a larger integer value for the principal quantum number indicates a larger radius and higher energy. This is similar to gravitational potential energy”

Question 13

“The second quantum number is called the _______ quantum number and is designated by the letter l”

Answer 13

azimuthal (angular momentum)

“For any principal quantum number n, there will be n possible values for l, ranging from 0 to (n – 1).”

0=s
1=p
2=d
3=f

“Thus, an electron in the shell n = 4 and subshell l = 2 is said to be in a 4d subshell

Question 14

Way to find Maximum number of electrons within a subshell =

Answer 14

4l + 2”

“where l is the azimuthal quantum number. The energies of the subshells increase with increasing l value; however, the energies of subshells from different principal energy levels may overlap. For example, the 4s subshell will have a lower energy than the 3d subshell.”

Question 15

“The third quantum number is the ________ and is designated ml”

Answer 15

Magnetic Quantum number

The magnetic quantum number specifies the particular orbital within a subshell where an electron is most likely to be found at a given moment in time”
(px,py,pz)

“For any value of l, there will be 2l + 1 possible values for ml”

“For any n, this produces n^2 orbitals”

Question 16

“The possible values of ml are the integers between

Answer 16

–l and +l, ”

Question 17

“The fourth quantum number is called the ________ and is denoted by _____”

Answer 17

spin quantum number; ms”

Question 18

“The ______ rule can be used to rank subshells by increasing energy.

Answer 18

(n + l) rule

This rule states that the lower the sum of the values of the first and second quantum numbers (n + l), the lower the energy of the subshell. This is a helpful rule to remember for Test Day. If two subshells possess the same (n + l) value, the subshell with the lower n value has a lower energy and will fill with electrons first.

Question 19

“What is the electron configuration of Fe3+?”

Answer 19

[Ar] 3d5

“The electron configuration of iron is [Ar] 4s23d6. Electrons are removed from the 4s subshell before the 3d subshell because it has a higher principal quantum number.”

If multiple subshells are tied “for the highest n value, then electrons are removed from the subshell with the highest l value among these.”

Excerpt From: Kaplan. “Kaplan MCAT General Chemistry Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.

Question 20

“An important corollary from Hund’s rule is that ______ and _____orbitals have lower energies (higher stability) than other states. ”

Answer 20

half-filled and fully filled

Question 21

“Materials composed of atoms with unpaired electrons will orient their spins in alignment with a magnetic field, and the material will thus be weakly attracted to the magnetic field. These materials are considered

Answer 21

paramagnetic.”

Question 22

“Materials consisting of atoms that have all paired electrons will be slightly repelled by a magnetic field and are said to be

Answer 22

diamagnetic

Question 23

“For elements in Groups IA and IIA (Groups 1 and 2), only the _______ electrons are valence electrons. For elements in Groups IIIA through VIIIA (Groups 13 through 18), _________ electrons are valence electrons”

Answer 23

highest s subshell; the highest s and p subshell electrons

“For transition elements, the valence electrons are those in the highest s and d subshells, even though they do not have the same principal quantum number.”

Question 24

“For transition elements, the valence electrons are those in the _______subshells, even though they do not have the same principal quantum number.”

Answer 24

highest s and d subshells

“For the lanthanide and actinide series, the valence electrons are those in the highest s and f subshells, even though they have different principal quantum numbers. ”

Question 25

“All elements in period three (starting with sodium) and below may accept electrons into their d subshell, which allows them to hold more than eight electrons in their valence shell. This allows them to violate the ______

Answer 25

octet rule”

Question 26

“is essentially equal to the mass number, the sum of an element’s protons and neutrons.”

Answer 26

Atomic Mass

“Atomic weight is the weighted average of the naturally occurring isotopes of an element. The Periodic Table lists atomic weights, not atomic masses.”

Question 27

first postulated that the atom had a dense, positively charged nucleus that made up only a small fraction of the volume of the atom.”

Answer 27

“Rutherford

Question 28

“In the __________, a dense, positively charged nucleus is surrounded by electrons revolving around the nucleus in orbits with distinct energy levels.”

Answer 28

Bohr Model of the atom

Question 29

“The energy difference between energy levels is called a ______, first described by Planck”

Answer 29

Quantum

Question 30

“Quantization means that there is not an infinite range of energy levels available to an electron; electrons can exist only at certain energy levels. The energy of an electron __________ the farther it is from the nucleus.”

Answer 30

Increases

Question 31

“The quantum mechanical model posits that electrons do not travel in defined orbits but rather are localized in _______; a region of space around the nucleus defined by the probability of finding an electron in that region of space.”

Answer 31

orbitals

Question 32

“The principal quantum number, n, describes

Answer 32

the average energy of a shell.

The azimuthal quantum number, l, describes the subshells within a given principal energy level (s, p, d, and f).
The magnetic quantum number, ml, specifies the particular orbital within a subshell where an electron is likely to be found at a given moment in time.
The spin quantum number, ms, indicates the spin orientation of an electron in an orbital.”

Question 33

The azimuthal quantum number, l, describes

Answer 33

the subshells within a given principal energy level (s, p, d, and f).

Question 34

“The magnetic quantum number, ml, specifies

Answer 34

the particular orbital within a subshell where an electron is likely to be found at a given moment in time.”
(-l,l)

Question 35

“Electrons fill the principal energy levels and subshells according to increasing energy, which can be determined by the

Answer 35

(n + l) rule.”

Question 36

________materials have unpaired electrons that align with magnetic fields, attracting the material to a magnet.
________ materials have all paired electrons, which cannot easily be realigned; they are repelled by magnets.”

Answer 36

Paramagnetic; Diamagnetic

Question 37

What is planks relation to wavelength

Answer 37

E=hc/wavelenghth

Question 38

What is planks relation to frequency

Answer 38

E=hf

Question 39

“This electrostatic attraction between the valence shell electrons and the nucleus is known as ________, a measure of the net positive charge experienced by the outermost electrons.”

Answer 39

the effective nuclear charge (Zeff)

“ For elements in the same period, Zeff increases from left to right. ”

“Zeff is more or less constant among the elements within a given group” cuz increased shielding cancels increased nucleus positivity

Question 40

“The _____ of an element is thus equal to one-half of the distance between the centers of two atoms of an element that are briefly in contact with each other”

Answer 40

Atomic Radius

Question 41

“The Zeff _______ left to right across a period, and as a result, atomic radius ______ from left to right across a period.”

Answer 41

Increases, Decreases

Question 42

“Atomic radius is essentially opposite that of all other periodic trends. While others increase going up and to the right, atomic radius increases

Answer 42

going down and to the left.”

Question 43

“As we move down a group, the increasing principal quantum number implies that the valence electrons will be found farther away from the nucleus because the number of inner shells is increasing, separating the valence shell from the nucleus. Although the Zeff remains essentially _______, the atomic radius increases down a group. ”

Answer 43

CONSTANT!

Question 44

“In order to understand ionic radii, we must make two generalizations. One is that metals lose electrons and become ______, while nonmetals gain electrons and become ______. The other is that metalloids can go in either direction, but tend to follow the trend based on which side of the metalloid line they fall on. ”

Answer 44

Positive, Negative

Question 45

“For nonmetals close to the metalloid line, their group number dictates that they require more electrons than other nonmetals to achieve the electronic configuration seen in Group VIIIA. These nonmetals gain electrons while their nuclei maintain the same charge. Therefore, these nonmetals close to the metalloid line possess a _______ ionic radius than their counterparts closer to Group VIIIA.”

Answer 45

Larger

Question 46

“Ionization energy (IE), also known as ionization potential, is

Answer 46

the energy required to remove an electron from a gaseous species.”

“ Removing an electron from an atom always requires an input of heat, which makes it an endothermic process”

Question 47

“ Removing an electron from an atom always requires an input of heat, which makes it an _______ process”

Answer 47

endothermic

Question 48

“The energy necessary to remove the first electron is called the ________; the energy necessary to remove the second electron from the univalent cation (X+) to form the divalent cation (X2+) is called the, and so on.”

Answer 48

first ionization energy; second ionization energy

Question 49

The degree to which the IE increases provides clues about the identity of the atom. If losing a certain number of electrons gives an element a noble gas-like electron configuration, then removing a subsequent electron will cost _______ energy”

Answer 49

Much More

First IE of Mag=738
Second IE of Mag=1450
3rd IE of Mag= 7730

Question 50

are among the elements with the highest ionization energies.”

Answer 50

“ noble gases

Question 51

Halogens, By acquiring one additional electron, a halogen is able to complete its octet and achieve a noble gas configuration. This ______ process expels energy in the form of heat.”

Answer 51

Exothermic

Question 52

“refers to the energy dissipated by a gaseous species when it gains an electron.

Answer 52

Electron Affinity

Note the electron affinity is essentially the opposite concept from ionization energy. Because this is an exothermic process, ΔHrxn has a negative sign; however, the electron affinity is reported as a positive number. This is because electron affinity refers to the energy dissipated:”

Question 53

“the higher the ionization energy, the _______ the electronegativity.”

Answer 53

Higher

Question 54

“Electronegativity ______ across a period from left to right and ______ in a group from top to bottom. ”

Answer 54

Increases, Decreases

Question 55

\_\_\_\_\_\_ = largest, least electronegative, lowest ionization energy, least exothermic electron affinity
\_\_\_\_\_ = smallest, most electronegative, highest ionization energy, most exothermic electron affinity”

Excerpt From: Kaplan. “Kaplan MCAT General Chemistry Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.

Answer 55

Cesium, Fluorine

Question 56

\_\_\_\_ →\_\_\_\_\_
Atomic radius ↓
Ionization energy ↑
Electron affinity ↑
Electronegativity ↑

\_\_\_\_\_ →\_\_\_\_\_\_\_
Atomic radius ↑
Ionization energy ↓
Electron affinity ↓
Electronegativity ↓”

Answer 56

Left to right; Top to bottom

Question 57

“Together, the alkali and alkaline earth metals are called ______ because they are so reactive that they are not naturally found in their elemental (neutral) state.”

Answer 57

The active metals

Question 58

“The ________ (Group VIA or Group 16) are an eclectic group of nonmetals and metalloids. While not as reactive as the halogens, they are crucial for normal biological functions. They each have six electrons in their valence electron shell and, due to their proximity to the metalloids, generally have small atomic radii and large ionic radii”

Answer 58

Chalcogens

Question 59

“The noble gases (Group VIIIA or Group 18) are also known as inert gases because they have minimal chemical reactivity due to their filled valence shells. They have _____ ionization energies, little or no tendency to gain or lose electrons, and (for He, Ne, and Ar, at least), no measurable electronegativities. ”

Answer 59

High

Question 60

“Many transition metals act as _______ for enzymes, including vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc.”

Answer 60

Cofactors

Question 61

“increases from left to right across a period, with little change in value from top to bottom in a group.”

Answer 61

Jeff

Effective Nuclear Charge

Question 62

“Cations are generally _______ than their corresponding neutral atom.
Anions are generally _______ than their corresponding neutral atom.”

Answer 62

Smaller, Larger

Question 63

“is the amount of energy necessary to remove an electron from the valence shell of a gaseous species; it increases from left to right across a period and decreases from top to bottom in a group.”

Answer 63

Ionization energy

Question 64

“is the amount of energy released when a gaseous species gains an electron in its valence shell; it increases from left to right across a period and decreases from top to bottom in a group.”

Answer 64

Electron Affinity

Question 65

“is a measure of the attractive force of the nucleus for electrons within a bond; it increases from left to right across a period and decreases from top to bottom in a group.”

Answer 65

Electronegativity

Question 66

List the incomplete octet atoms that are stable

Answer 66

“These elements are stable with fewer than eight electrons in their valence shell and include hydrogen (stable with 2 electrons), helium (2), lithium (2), beryllium (4), and boron (6).”

Question 67

“Any element in period 3 and greater can hold more than eight electrons, including phosphorus (10), sulfur (12), chlorine (14), and many others.”

Answer 67

Expanded Octet

Question 68

“If both of the shared electrons are contributed by only one of the two atoms, the bond is called

Answer 68

coordinate covalent.”

Question 69

“Because of the strength of the electrostatic force between the ionic constituents of the compound, ionic compounds have very high

Answer 69

melting and boiling points”

“Many ionic compounds dissolve readily in aqueous and other polar solvent solutions and, in the molten or aqueous state, are good conductors of electricity.”

Question 70

“In the solid state, the ionic constituents of the compound form a ____ ____consisting of repeating positive and negative ions”

Answer 70

crystalline lattice

Question 71

“The number of shared electron pairs between two atoms is called the ______; hence, a single bond has a bond order of one, a double bond has a bond order of two, and a triple bond has a bond order of three. ”

Answer 71

Bond order

Question 72

“is the average distance between the two nuclei of atoms in a bond. As the number of shared electron pairs increases, the two atoms are pulled closer together, resulting in a decrease in bond length. Thus, for a given pair of atoms, a triple bond is shorter than a double bond, which is shorter than a single bond”

Answer 72

Bond Length

Question 73

“The greater the number of pairs of electrons shared between the atomic nuclei, the more energy is required to break the bonds holding the atoms together. Thus, triple bonds have the ______ bond energy, and single bonds have the _____ bond energy. ”

Answer 73

Greatest; Lowest

Question 74

“Note that only bonds between atoms of the same element will have exactly the same electronegativity and therefore exhibit a purely equal distribution of electrons. The seven common diatomic molecules are

Answer 74

H2, N2, O2, F2, Cl2, Br2, and I2.”

“Here’s a quick way to remember the naturally occurring diatomic elements on the Periodic Table: they form the number 7 on the Periodic Table (except for H), there are 7 of them, and most of them are in Group VIIA: H2, N2, O2, F2, Cl2, Br2, I2.”

Question 75

“The dipole moment of the polar bond or polar molecule is a vector quantity given by the equation:

Answer 75

p = qd

“where p is the dipole moment, q is the magnitude of the charge, and d is the displacement vector separating the two partial charges. The dipole moment vector, represented by an arrow pointing from the positive to the negative charge, is measured in Debye units (coulomb–meters).”

Question 76

“A Lewis acid is any compound that will _______ a lone pair of electrons, while a Lewis base is any compound that will ______ a pair of electrons to form a covalent bond.”

Answer 76

Accept; Donate

AAAAAcids AAAAAccept

NH3 donates a pair of electrons to form a coordinate covalent bond; thus, it acts as a Lewis base. At the same time, BF3 accepts this pair of electrons to form the coordinate covalent bond; thus, it acts as a Lewis acid.”

Question 77

“In general, the least electronegative atom is the ______ atom. Hydrogen (always) and the halogens F, Cl, Br, and I (usually) occupy a terminal position.”

Answer 77

Central

Question 78

“formal charge _______ the effect of electronegativity differences, whereas oxidation numbers ________ the effect of electro-negativity differences, assuming that the more electronegative atom has a 100 percent share of the bonding electron pair. ”

Answer 78

Underestimates, Overestimates

“or example, in a molecule of CO2 (carbon dioxide), the formal charge on each of the atoms is 0, but the oxidation number of each “of the oxygen atoms is −2 and of the carbon is +4. In reality, the distribution of electron density between the carbon and oxygen atoms lies somewhere between the extremes predicted by the formal charges and the oxidation states.”

Question 79

“One can use formal charge to assess the stability of resonance structures according to the following guidelines:”

Answer 79

1. A Lewis structure with small or no formal charges is preferred over a Lewis structure with large formal charges
2. “A Lewis structure with less separation between opposite charges is preferred over a Lewis structure with a large separation of opposite charges”

3.A Lewis structure in which negative formal charges are placed on more electronegative atoms is more stable than one in which the negative formal charges are placed on less electronegative atoms”

Question 80

“It states that the three-dimensional arrangement of atoms surrounding a central atom is determined by the repulsions between bonding and nonbonding electron pairs in the valence shell of the central atom.”

Answer 80

“Valence Shell Electron Pair Repulsion (VSEPR) Theory”

Question 81

“In the worked example, notice that the ammonia molecule has a tetrahedral _______ structure, but is considered to have a _______ structure that is trigonal pyramidal.”

Answer 81

Electronic, Molecular

Question 82

“describes the spatial arrangement of all pairs of electrons around the central atom, including both the bonding and the lone pairs.”

Answer 82

Electronic geometry

“he molecular geometry describes the spatial arrangement of only the bonding pairs of electrons.”

Question 83

“CH4, NH3, and H2O all have a _______ electronic geometry, but differ in their molecular shapes:
CH4 is tetrahedral, NH3 is pyramidal, and H2O is bent or angular.”

Answer 83

Tetrahedral

Question 84

“ Tetrahedral electronic geometry, for example, is associated with an ideal bond angle of 109.5°; however, _________ pairs (electrons) are able to exert more repulsion than bonding pairs because these electrons reside closer to the nucleus. Thus, the angle in ammonia is closer to 107°, and the angle in water is 104.5°.

Answer 84

Nonbonding

Question 85

In doing lewis structures Compounds with an odd number of electrons cannot have

Answer 85

eight electrons on each element.”