Exam 1: Atoms and Molecules Flashcards by Rory Edwards

Development of Atomic Theory

Who discovered the electron?

JJ Tompson

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Development of Atomic Theory

How was the electron discovered?

What expirement?

Cathode Ray Expirement

Particles deflected based on charge

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Development of Atomic Theory

JJ Thompsons model of the atom

Plum Pudding Model

Negative electrons, surrounded by positivity

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Development of Atomic Theory

Who discovered the nucleus? With what expirement?

Ernest Rutherford, Gold Foil Expirement

Alpha Particles pass through gold foil and bounce of nucleus

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Development of Atomic Theory

What atomic model came of the Gold Foil Expirement?

Rutherford Model

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Quantum Mechanics

Quantum Mechanics explains…

behaviour of microscopic matter

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Classical Mechanics

According to Classical Mechanics is light a particle or a wave?

CLASSICAL MECHANICS

Wave

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Classical Mechanics

F= (Q1)(Q2)/(4)(π)(ε)(r²)

Coulomb’s Force Law is used for…

Q= charge of particles
ε = permivitity constant
r = distances between pa

Force between 2 charged particles

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Classical Mechanics

F=(m)(a)

Newton’s Second Law states…

F= force applied to particle
m= mass of particle
a= acceleration of particle

how fast particles are moving

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Classical Mechanics

Classical Mechanics fails because…

it does not explain microscopic particle behaviour.

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Quantum Mechanics

What two assumptions are made in Quantum Mechanics

Radiation and matter display wave-like and particle-like properties (wave-particle duality)
Energy is quanticed into discrete packets (photons)

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Quantum Mechanics - Wave-Particle Duality

Lambda

Wavelength: Distance between two successive maxima (or minima)

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Quantum Mechanics - Wave-Particle Duality

Frequency: Number of cycles per unit time

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Unit Conversions

m to nm

m x 10^-9

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Unit Conversions

nm to m

nm/10^-9

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Light as a Wave

Causes periodic variation of ____ and ____ field

Electric and Magnetic

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Light as a Wave

Emits ____ radiation

Electromagnetic

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Light as a Wave

c = λμ

c = constant for electromagnetic waves

c = speed of wave (light) (m/s)
λ = wavelength (m)
μ = frequency (s^-1)

c = 2.9979 x 10^8 m/s

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Colour of Light

Red has a ____ wavelength?

High

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Colour of Light

Purple has a ____ wavelength?

Low

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Colour of Light

Red has a ____ frequency

Low

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Colour of Light

Purple has a ____ frequency

High

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Wave Interaction

Define superposition

The result when two or more waves interact

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Wave Interaction

Constructive interference is____

When two waves meet and there absolute amplitudes increase

Max + Max or Min + Min

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# Wave Interactiopn Destructive Interference is ____

When two waves meet and their amplitudes cancel out | Max + Min

# Wave Interference At superposition wavelength and frequency of the waves change | True or False

False | Wavelength and frequency of the wave(s) does not change

# Wave Interaction Thomas ____'s ____ expirement proved ____ | Name, Expirement Name, Expirement Purpose

Young, Double Slit Expirement, Light has wave properties

# Photoelectric Effect Electrons ejected if: 1. Frequency of light is less than the metal's threshold frequency 2. Metal's threshold frequency is less than the frequency of light | Choose 1 or 2

# Photoelectric Effect Number of electrons ejected increases as frequncy increase after the threshold frequency | True or False

False | After the threshold frequency the number of electrons is constant

# Photoelectric Effect Kinetic Energy (KE) of ejected electrons stays constant as frequency increase after the threshold frequency. | True or False

False | KE increases as frequency increases

# Photoelectric Effect Light intensity (photons/second) has no affect on Kinetic Energy | True or False

True

# Photoelectric Effect Number of electrons ejected increases as light intensity increases | True or False

True

# Kinetic Energy Equation KE = Ei - Φ

KE = Kinetic Energy Ei = hµ = hc/λ = Energy of incident light Φ = hµ (threshold frequency) = workfunction

# New Photoelectric Effect If KE is _ than zero there are no electrons ejected | Fill in the Blank

≤ Less than

# New Photoelectric Effect Number of electrons ejected is always less than the number of photons applied. | True or False

False | Number of electrons out = Number of photons in

# Unit Conversion eV to J | How to convert?

x (1.6022 x 10^-19) | Number on Equation Package

# Unit Conversion J to eV

J / (1.6022 x 10^-19) | Number on Equation Package

# Photon Momentum DeBroglie Wavelength Equation | Can be determined by equations on Equation Package

λ = h/mv

# Schrodinger Equation GP Thomson discovered light's .... | He is also the son of ...

Wave-like properties | JJ Thomson

# Schrodinger Equation (Hydrogen) The gorund state is the ____ energy level and it is the ____ stable state | Fill in the blanks

Lowest, most

# Schrodinger Equation En = -RH/n^2 This is the equation for binding energy of all atoms | Define variables and answer True or False

En = binding energy RH = Rydberg's Constant (on Equation Package) n = Principle Quantum Number False | This is the equation for Hydrogen ONLY with one elecetron

# Binding Energy For any one electron systems binding energy is equal to En = -(Z^2)(RH)/n^2 | True or False then define Z

True Z = atomic number

# Binding Energy Binding energy is always.... | + or -

Negative

# Binding Energy A free electron has a binding energy > zero | True or False

False | Free electrons have 0 binding energy

# Binding Energy Consider the binding energy equation... 1. As n increases binding energy gets more negative and therefore electron is strongy bound 2. As Z increases binding energy gets more negative and therefore electron is weakly bound | True or False for each

1. False, as n increases binding energy gets less negative causing weakly bound electrons 2. False, as Z increase binding energy gets more negative causing strongly bound electrons

# Ionization Energy and Binding Energy En = -IE | Define and explain both sides of the equation

En = Binding energy and is always negative IE = Ionization energy and is always positive

# Ionization Energy Ionization energy is the ____ energy needed to ____ electron | Fill in the blanks

minimum, remove

# Ionization Energy Ionization energy is always > zero | True or False

True | IE is always positive

# Photon Emission Electron goes from ____ n state to ____ low n state | Fill in the blanks

high, low | High to Low

# Photon Emission Electromagnetic Radiation is...

Photon Emission

# Photon Emission ∆E = Ei - Ef | Define Variables

∆E = Change in energy = energy of photon emitted Ei = energy at initial n state Ef = energy at final n state

# Balmer Series ____ Balmer discovered that H atoms emit visable light in the year ____ | Fill in the blanks

JJ, 1885

# Photon Emission Large ∆E means ____ µ and ____ λ | Fill in the blanks

high, low

# Photon Emission Low µ and high λ results from a ____ ∆E | Fill in the blank

Small

# Photon Emission µ = [(Z^2)(RH)/h] [(1/nf^2)-(1/ni^2)] | Define Variables

Z = atomic number RH = Rydberg's constant h = Planck's constant nf = final n state ni = initial n state

# Photon Absorbtion Photon absorbtion is the ____ of photon emission. It occurs when photon goes from ____ n state to ____ n state. | Fill in the blanks

opposite/reverse, low, high | Low to High

# Photon Absorbtion µ = [(Z^2)(RH)/h] [(1/ni^2)-(1/nf^2)] | Define Variables

Z = atomic number RH = Rydberg's constant h = Planck's constant ni = initial n state nf = final n state

# Wavefunctions Wavefunction Symbol

𝚿

# Wavefunctions Wavefunctions depend on which 3 quantum numbers?

n, l, ml

# Wavefunction Shapes Degenerate wavefunctions (orbitals) have the same ____ and therefore same ____ | Fill in the blanks

n value, energy

# Wavefunction Shapes Number of degenerate orbitals (wavefunctions) equal...

n^2

# Wavefunction Composition 𝚿 = radial wavefunction x angular wavefunction | Define terms

Radial Wavefunction: dependent on n and l Angular Wavefunction: dependent on l and ml

# Wavefunction Composition s orbitals are ____ symetric so all s orbitals share the same value for ____ wavefunction | Fill in the blanks

spherically, angular

# Wavefunction Composition Wavefunctions of s orbitals are dependent on radial or angular wavefunction? | Explain why

Radial because it is independent of θ and Φ therefore angular wavefunction is consistant across all s orbitals (spherical symetry)

# Wavefunction Composition All p orbitals have l = ____, so their ____ wavefunctions are all the same | Fill in the blanks

1, radial

# Wavefunction Composition p orbitals' wavefunctions depend on their angular or radial wavefunctions? | Explain why

Angular because all p orbitals share a radial wavefunction, and angular wavefunctions differ due to differing ml values

# Nodes Radial nodes occur when a radius causes 𝚿 = ?

# Nodes Angular nodes occur when ____ cause 𝚿 = 0 | Fill in the blank

θ and Φ/ angles

# Nodes Number of radial nodes =

n - 1 - l

# Nodes Number of angular nodes =

# Nodes Total number of nodes =

n-1

# Radial Probability Distribution (RPD) RPD graphs plot...

Probability of finding an electron at a certain radius

# Radial Probability Distribution The highest point on a RPD (rpm) is ...

The value of r (the radius) where there is most likely to be an electron

# Radial Probability Distribution Radial nodes occur when RPD function ...

touches x-axis/ equals zero

# Radial Probability Distribution As n increases, rpm...

increases

# Radial Probability Distribution As l increaes, rpm...

decreases

# Multi Electron Systems When describing an orbital ____ quantum number(s) should be used | Fill in the blank with a number

# Multi Electron Systems When describing an electron ____ quantum number(s) should be used | Fill in the blank with a number

# Multi Electron Systems Aufbau's Principle says:

Electrons fill orbitals in order of lowest energy state to highest energy state

# Multi Electron Systems Hund's Rule states:

A single electron occupies each orbital in each energy state before doubling up, and all single electrons are spin up.

# Multi Electron Systems Pauli's Exclusion Principle states:

No two electrons can have the same exact quantum numbers, so when electrons share an orbital one will be spin up and the other spin down (ms = +1/2 vs. ms = -1/2)

# Multi Electron Systems Binding energy depends on ____ and ____ quantum numbers | Fill in the blanks

n, l

# Multi Electron Systems Enl = -IEnl = -(Zeff^2)(RH)/n^2 | Define variables

Enl = Binding energy of multi electron system IEnl = Ionization energy of multi electron system Zeff = Effective charge (from sheilding effect) RH = Rynberg's constant n = Principle quantum number

# Sheilding Effect Zeff should always be between Z is there was ____ sheilding and Z is there was ____ sheilding | Fill in the blanks

no, complete | Reminder: Z = atomic number, sheilding effect changes charge

# Electron Configurations Which 2 elements have exceptions to Aufbau's principle? Why?

Cr and Cu because half filled and fully filled d orbitals are favoured over s orbitals. | d orbital steals electron from s orbital

# Electron Configurations s orbitals contain ____ electrons, p orbitals contain ____ electrons, d orbitals contain ____ electrons, f orbitals contain ____ electrons | Fill in the blanks with numbers

2, 6, 10, 14

# Periodic Trends On the periodic table, n quantum number is represented by.... | Details!!!!!

Period | Groups 3 - 12 see that n = period number -1

# Periodic Trends On the periodic table, groups ____ and ____ will have their valence electrons in s orbitals | Fill in the blanks with numbers

1 and 2

# Periodic Trends On the periodic table, groups ____ to ____ will have their valence electrons in p orbitals | Fill in the blanks with numbers

13 to 18

# Periodic Trends On the periodic table, groups ____ to ____ will have their valence electrons in d orbitals | Fill in the blanks with numbers

3 to 12

# Periodic Trends On the periodic table, which elements have their valance electrons in f orbitals?

Special elements (atomic numbers 57-71 and 89-103)

# Quantum Numbers n is the...

principle quantum number

# Quantum Numbers l =

n-1

# Quantum Numbers l = 0 results in which orbital

# Quantum Numbers l = 1 results in which orbital

# Quantum Numbers l = 2 results in which orbital

# Quantum Numbers l = 3 results in which orbital

# Quantum Numbers ml =

range from -l to +l

# Quantum Numbers ms =

+1/2 or -1/2

# Ions Electron Configurations Once a d orbital is filled (when an atom becomes ionized) the electrons are removed from previous s orbital | True or False

True

# Electron Configurations Isoelectronic ions and atoms are...

ions and atoms that have the same electron configurations

# Periodic Trends Describe the trend of IE in terms of the periodic table

IE increase as you move up and right across the periodic table

# Periodic Trends Describe the trend of Electron Affinity (EA) in terms of the periodic table

EA increase as you move up and right across the periodic table

# Periodic Trends Describe the trend of Electronegativity (X) in terms of the periodic table

X increase as you move up and right across the periodic table

# Periodic Trends Describe the trend of Atomic Radius in terms of the periodic table | Ionic Radius?

Atomic Radius increase as you move down and left across the periodic table | Increases as you move down the periodic table

# Periodic Trends What are the exceptions to the IE periodic trend?

Half full/ full orbitals are more stable and therefore favoured, so they have higher than expected ionization energies

# Periodic Trends What are the exceptions to the EA periodic trend?

Noble Gases are stable and do not seak stability therefore they have very negative EA

# Bonding Chemical bonding is the arrangment of atoms that result in ____ ____ energy than the atoms have seperatley

more negative

# Periodic Trends What are the exceptions to the X periodic trend?

Noble Gases are stable and do not seak electrons therefore they have X = 0

# Bonding The complete transfer of electrons is which type of bonding? | Ionic, Covalent, Polar-Covalent

Ionic

# Bonding Ionic bonding results in a ∆X

≥1.7

# Bonding Covalent bonding is when an electron pair is ____ shared between two atoms | Fill in the blank

equally

# Bonding ∆X ≤ 0.4 is a result of which type of bonding? | Ionic, Covalent, Polar-Covalent

Covalent

# Bonding An unqual sharing of an electron pair is what type of bonding? | Ionic, Covalent, Polar-Covalent

Polar-Covalent

# Bonding Polar-Covalnet bonds have ∆X =

0.4-1.7

# Bonding Dissociation Energy is...

The amount of energy required to break a chemical bond and seperate chemically bonded atoms

# Lewis Structures In step 1, when drawing Lewis Structures, which atom goes in the middle?

The atom with the lowest IE

# Lewis Structures In step 2, when drawing Lewis Structures, one should total the number of...

Valence electrons

# Lewis Structures In step 3, when drawing Lewis Structures, one should total...

The number of electrons in full valence shells

# Lewis Structures In step 3, when drawing Lewis Structures, one should total...

The number of electrons in full valence shells

# Lewis Structures In step 4, when drawing Lewis Structures, one should determine the number of bonding electrons by...

Subtracting valence electrons (step 2) from full valence electrons (step 3)

# Lewis Structures In step 5, when drawing Lewis Structures, one bond is made up of ____ bonding electrons | Fill in the blank with a number

# Lewis Structures In step 6, when drawing Lewis Structures, if there are bonding electrons remaining one should

include double/tripple bonds

# Lewis Structures In step 7, when drawing Lewis Structures, one should determine the number of loan pair electrons by...

Subtracting bonding electrons (step 4) from total valence electrons (step 3)

# Formal Charge Formal charge applies to ____ bonding only | Fill in the blank

Covalent

# Formal Charge FC =

V-L-B | V = valence electrons L = loan pair electrons B = number of bonds

# Formal Charge Formal Charge is the extent to which an atom has lost/gained an electron | True or False

True

# Formal Charge How does formal charge relate to the charge of the molecule?

Sum of FC of each atom = molecule charge

# Formal Charge Lewis structures with highest absolute FC are the most stable and therefore have the lowest energy | True or False

False | *lowest absolute FC

# Formal Charge Negative FC = most electrnegative = most stable = highest energy | True or False

False | *lowest energy

# Resonance Structures All molecules have resonance structures | True or False

False

# Resonance Structures Resonance structures have ____ atom arrangment and ____ bond arrangment | Fill in the blanks

same, different

# Resonance Structures FC is constant across resonance structures | True or False

True

# Octet Rule Exceptions When there is an odd number of valence electrons it is impossible for...

all atoms to have complete octets

# Octet Rule Exceptions A radical species is a result of...

An unpaired electron from an odd number of valence electrons

# Octet Rule Exceptions Which two elements will be octet difficent (have incomplete octets)

Al and B | Aluminium and Boron

# Octet Rule Exceptions Which elements are eligable for valence shell expansion (expanded octet)?

Central elements with n ≥ 3, and empty d orbitals