Atomic structure, Periodic Table, Bonding and Chemical Interactions, and the Gas Phase

Question 1

What is 1 amu (atomic mass unit) in terms of 12-C carbon atom?

Answer 1

1/12 of one 12-Carbon atom

1 proton = 1 amu

Question 2

How many atoms are in a mole?

Answer 2

6.022 X 10^23 atoms in a mole

Question 3

How many grams is equal to one mole of amu?

Answer 3

1 g = 1 mol of amu

Question 4

What is the equation for the energy of quantum? (for a *single photon)

Answer 4

E = hf = h (c/wavelength) = -R / (ni^2 - nf^2)

Question 5

How is the angular momentum related to the energy level from which the electrons fall in a hydrogen atom?

Answer 5

angular momentum is linearly and directly related to the energy level from which the hydrogen electrons fall. The hydrogen electrons falling from a greater energy level, releases greater angular momentum

Question 6

How is the wavelength of absorption and wavelength of emission different?

Answer 6

they are the same

Question 7

What’s Hund’s rule

Answer 7

Maximum number of half filled shells with parallel spins

Question 8

Paramagnetic vs. Diamagnetic

Answer 8

In a case of a magnetic field with unpaired electrons, a material with unpaired electron will align in the direction of the magnetic field. This is called paramagnetic, (para - side by side the magnetic field).

Diamagnetic: when the material is slightly repelled. The material has paired electrons.

Question 9

What is effective nuclear charge? How do you calculate Zeff? Why is Zeff special?

What is the trend of effective nuclear charge across the periodic table?

Why is it always less than the total number of protons present?

Which electrons in an atom produce the shielding effect?

Answer 9

The pull felt by the recently added e-, drawn by the protons in the nucleus. The net positive charge felt by the valence electrons. Zeff = Z - S (number of shielding electrons). Zeff is special because it explains all the other trends in the periodic table.

Always less than the actual Z because of shielding from the core electrons

Across the period because of the increase in charge with no increase in shielding effect. Decrease down the group because shielding effect becomes greater

Electrons toward the inner core (non-valence e-) produce the shielding effect. Electrons in the same shell do not produce shielding effects for each other from the attractive pull of the electrons

Question 10

What is the trend of atomic radius across the periodic table?

Answer 10

Francium has the largest atomic radius

increase down left toward Francium

Question 11

Is energy absorbed or released during ionization of an atom? In other words, is energy added or released to remove an electron?

Answer 11

endothermic process, you must input energy to remove and electron

Question 12

What is the trend of ionization energy across the periodic table? What are the exceptions?

Answer 12

Ionization energy generally increases from left to right

Question 13

Is energy absorbed or released when electron is added?

Answer 13

exothermic process, energy is released once electron is accepted

Question 14

What is electron affinity?

How can it be measured?

What is the trend across periodic table?

Answer 14

How much electron pair an atom wants

By measuring the released energy once electron is accepted.

Increase toward Fluorine

Question 15

Relationship between Zeff and Electron affinity (energy released when electron is accepted)?

Answer 15

Greater the effective nuclear charge, greater the energy released when electron is accepted

Question 16

What is electronegativity and what is its trend?

Answer 16

an attractive force an atom will exert in a chemical bond for electrons

Increase toward Fluorine

Question 17

How is electronegativity related to ionization energy?

Answer 17

Electronegativity values are directly related to ionization energies

Question 18

What is coordinate covalent?

Answer 18

When the shared electrons are contributed only by one atom

Question 19

For an ionic bond to occur, what must be the electronegativity difference?

Answer 19

The electronegativity must be greater than 1.7

Question 20

Relationship between bond energy and bond strength

Answer 20

positively correlated

Question 21

What is the equation for dipole moment?

Answer 21

Dipole moment = charge X radius (C*m)

Question 22

Angles of different molecular geometries:

Linear, Tetrahedral, trigonal pyramidal, bent, trigonal bipyramidal, trigonal planar, and octahedral

Answer 22

Linear: 180 
Tetrahedral: 109.5 
Trigonal: 120 
Trigonal pyramidal: 107 
Bent: 104.5
Trigonal bipyramidal 90, 120, 180 
Octahedral: 90, 180

Question 23

Heisenburg’s uncertainty principle

Answer 23

position and momentum of an electron cannot be known simultaneously

Question 24

Maximum number of electrons allowed in a single atomic energy level in terms of n

Answer 24

2n^2

Question 25

Ionization energy trend on the periodic table

Answer 25

increase toward F

Question 26

What’s higher: first or second ionization energy?

Answer 26

2nd ionization energy

Question 27

angular momentum quantum number

Answer 27

s, p, d, f (0, 1, 2, 3)

Question 28

Magnetic quantum number

Answer 28

ml; describes the specific orbital the electron is in, orientation (orbital)

Question 29

Pauling scale of E-: what does it measure?

What is the pauling scale for non-polar, polar covalent, and ionic bonding?

Answer 29

Measures electronegativity

non-polar: less than 0.5
polar covalent: between 0.5 to 1.6
Ionic: 1.7 and up

0-4, fluorine being 4

Question 30

How is energy of a photon related to speed of the wave, frequency and wavelength in an equation?

Answer 30

E = hf = hc/wavelength

Question 31

Closer an electron is to the nucleus, the ____ its energy and the more ____ it is held

Answer 31

the closer an electron is to the nucleus, the lower its energy and the more tightly it is held.

Question 32

The impact of the size of the nucleus on atomic radius

Answer 32

the size of the nucleus has almost zero impact on the “size” of the atom, which is due to the number of electrons.

Question 33

Equation for photoelectric effect

Answer 33

hf = energy to eject electron + kinetic energy of ejected electron

hf = work function + 1/2mv^2

h(frequncy) = h(initial frequency) + kinetic energy of the electrons.

Question 34

What is the relationship between the kinetic energy and frequency of incident photons?

What is the threshold frequency?

Answer 34

directly related;

the threshold frequency is the minimum frequency required to remove the electrons from the outer orbits;

Question 35

First order decay vs. zero-order decay

difference in terms of half-life

Answer 35

First order decay: half life is the same consistently. It takes the same amount of time to decrease the concentration from 50 to 25 and from 25 to 12.5. The rate of change in concentration decreases linearly with time.

Zero order decay: half life decreases linearly with the concentration. So if the concentration decreases by 50% the half life also changes by 50%. The the rate of change in concentration remains constant over time.

Question 36

What is Planck’s quantum theory?

Answer 36

E = h*frequency

Question 37

How to wavelength related to mass, and velocity?

Answer 37

inversely related

Wavelength = h/mv

Question 38

What is the minimum energy required to eject an electron?

Answer 38

aka the work function; energy of photon minus the kinetic energy of ejected electron

h*f - KE = work function

Question 39

How do you increase the intensity of light to increase energy? How does increasing the wavelength affect the intensity of light?

Answer 39

increase frequency, not wavelength. Increasing the wavelength does not increase the intensity of light or energy

Question 40

What is a mean free path

Answer 40

Distance travelled by a gas molecule between collisions

Question 41

Does polarity affect the homogeneity of the gases?

Answer 41

Polarity does not affect homogeneity. Gases mix regardless of polarity. Given time and low temperature, most dense gas will settle at the bottom however.

Question 42

What is the equation that relates the average translational kinetic energy and the temperature of the gas? Can you use this relationship on any fluids?

Answer 42

The average kinetic energy is 3/2 * R*T

Can be used in any fluid system

Question 43

Binding energy

Answer 43

Energy needed to break protons and neutrons

Question 44

Strong nuclear force

Answer 44

Force that keeps protons and neutrons together

Question 45

Charge of 1e-

Answer 45

1.6 X 10^-19 coulombs

Question 46

Metals

Answer 46

Large atoms that tend to lose electrons to form positive ions and positive oxidation states.

Atom in a sea of electrons (fluid like nature of valence electrons)

Ductile, malleable, lustrous, thermally and electrically conductive.

Question 47

Ductility vs. malleability

Answer 47

Stretching vs. Thin strips

Question 48

Energy of a single photon

Answer 48

Change in energy of photon is

h * frequency

Question 49

Wave characteristics of electrons and other moving masses

Answer 49

Wavelength = h / mass * velocity

Question 50

what is the shielding effect?

Answer 50

the balance of the pull from the protons and the repulsion from surrounding electrons resulting in decreased positive charge felt by electrons due to core electrons (non-valence electrons)

Question 51

What is an ionization energy?

Answer 51

energy released when an electron is ripped off