Unit 2 Exam

Question 1

Daltons Atomic Theory

Answer 1

1. All atoms of a given element are identical (except Isotopes)
2. Atoms of different elements have different masses
3. compounds are made of different elements combined in specific ratios
4. in a chemcal reaction atoms are neither created or destroyed

Question 2

Proton

Answer 2

Postively Charged particle

Question 3

Neutron

Answer 3

nuetral particle

Question 4

electron

Answer 4

negatively charged

Question 5

Necleus Characteristics

Answer 5

• contains protons and neutrons
• positive charge
• determines mass of atom
• extremely small, but dense

Question 6

Mass #

Answer 6

of protons plus # of neutrons

Question 7

Atomic Number

Answer 7

Number of Protons

Question 8

How to determine the # of neutrons

Answer 8

Mass # - atomic #

Question 9

Determine the # of electrons

Answer 9

of protons for a neutral atom

Question 10

Isotope

Answer 10

Something has the same # of protons but different # of neutrons

Question 11

Ion

Answer 11

charged particle formed by gain or loss of electron

(+) ion loss of electron

(-) ion gain of electron

Question 12

J.J. Thomson (1897)

Answer 12

Determined the charge to mass ratio of an electron

used the cathode ray tube (An electric field is set up between 2 plates, + and - charged and a magnetic field is applied perpendicular to the electric field and the electrons are fed between the the two plates)

Found that the charged particles (electrons) were the same regardless of the metal he used for the cathode.

Concluded that electrons are part of the makeup of all atoms

Question 13

Milliken Oil Drop Exp (1909)

Answer 13

Determined the charge of electron then using thomsons value calculated mass of an electron

Observed tiny electrically charged oil droplets. From the strength of the electric field required to overcome the pull of gravity on the droplets, he determined the values of the charges on the particle.

Experiment Setup: oil is sprayed as a fine mist into a chamber containing a charged gas, and the location of an oil drop is monitored by using a microscope. Charged particles (ions) are generated in the gas by exposing it to x-rays. The fall of the charged droplet is balanced by the electric field.

Question 14

Ernest Rutherford Exp (1908)

Answer 14

Determined nucleus (+) charge and very dense and atom is mostly empty space.

Experiment required shooting alpha particles toward a piece of platinum foil only a few atoms thick. Found almost all alpha particles passed through and were deflected only slightly (about 1 in 20,000 deflected more than 90 degrees). some bounced back straight in direction they had come.

When a positively charged alpa particle scored a direct hit on one of the minute but heavy platinum nuclei, the alpha particle was strongly repelled by the positive charge of the nucleus and deflected through a large angle.

Question 15

mass spectrometer

Answer 15

can measure the mass of isotopes and % abundances

Deflection depends on:

1. Magnitude of acclerating voltage
   
   1. higher voltage —-> beam moves more rapidly
      
      1. less deflection
2. magnitude field strength-stronger field deflects beam more
3. masses of particle-heavier particles deflected less
4. charges on particles
   
   1. higher charges are deflected more

Question 16

Steps for calculating average atomic mass

Answer 16

1. change % to decimal
2. multiply by mass
3. Add

Question 17

Wavelength

Answer 17

distance it takes for wave to repeat itself

C=λv

C=speed of light

v=frequency (given in Hz which is = to cycles/sec or s^-1)

Question 18

Energy Equation

Answer 18

E=hv

E=energy

h=planks constant

v=frequency

Question 19

Neils Bohr (1930’s?)

Answer 19

Said electrons have a quantum value—can only have certain values

farther from the necleus—-higher the energy

there are places you expect to find atoms then gaps where you don’t

Question 20

Balmer Series

Answer 20

visible spectrum

n₁ = 2

Question 21

Lyman Series

Answer 21

ultra-violet

n₁ = 1

Question 22

Bohr Frequency condition

Answer 22

V=Z²R( 1/n₁² - 1/n₂²)

R = Ryberg constant

Question 23

Photoelectric Effect

Answer 23

shows the particle (photon) nature of electromagnetic radiation

When light of sufficient energy strikes the metal, an electron is knocked off, it travels to the positive electrode and current flows to the circuit. ( see image)

Question 24

Classical Theory

Answer 24

If low levels of light are emitted long enough then it should

E_K = 1/2 mv² = hν−ϕ

ϕ = energy needeed to remove electron work function

hv= energy supplied by photon

Question 25

deBroglie Relationship

Answer 25

moving particles have wave properties

λ=h/mv p=mv λ=h/p

m=mass

h=planks constant

p=momentum

Question 26

Heisenberg Uncertainty Principle

Answer 26

∆p ∆x = 1/2 ħ

ħ = h(planks constant)/ 2π = 1.054 x 10^-34 J s

∆p= m∆v

Question 27

Schrodingers Equation

Answer 27

(-ћ²d²Ψ /2mdx²) + V(x) Ψ = EΨ

m= particle mass

V(x)= potential energy

probability of finding a particle is proportionate to Ψ ²

Question 28

Energies allowed for particle in the box

Answer 28

Question 29

Electron Shells

Answer 29

Main energy level; contains e- that are about same distance from nuclues and have about same energy

Question 30

Max number of e- in a shell

Answer 30

2n²

n= shell #

Question 31

subshells

Answer 31

contains e- that are same distance from the nucleus and have the same energy

of subshells is = to the shell #

labeled with shell # and a letter

Question 32

Orbitals

Answer 32

region of highest probability of finding an e-

Question 33

Max # of e- in any orbital

Answer 33

2e-

Question 34

radial nodes

Answer 34

1s—–0 radial nodes

2s——1 radial node

3s——-2 radial nodes

Question 35

Aufbau Principle

Answer 35

e- will usually occupy the lowest energy subshell available

Question 36

For (+) ion

Answer 36

e- are removed from the highest(outermost) shell

Question 37

Hund’s Rule

Answer 37

e- will fill orbitals singley before pairing

Question 38

Shell # for s and p elements

Answer 38

equals the row number

Question 39

shell # for d’s

Answer 39

= row#-1

Question 40

shell # for f’s

Answer 40

=row # - 2

Question 41

Electron config exceptions

Answer 41

Cu—s1d10

Ag—s1d10

Au—s1d10

Rg—s1d10

Cr—s1d5

Mo—s1d5

Ni—s2d8

Pd—d10

Pt—s1d9

Question 42

diamagnetic

Answer 42

all e- are paired

Question 43

paramagnetic

Answer 43

one or more unpaired e-

Question 44

Pauli Exclusion principle

Answer 44

no 2 e- in an atom can have the same set of quantum #’s

Question 45

Quantum numbers

Answer 45

n-shell

n,l - subshell

n,l,m_l - orbital

n,l,m_l,m_s - an e- in an orbital

Question 46

Representative elements

Answer 46

s and p blocks

Question 47

Periodic Group Names

Answer 47

Question 48

Atomic Radii (how big is an atom) Trend

Answer 48

Question 49

Ionization Energy

Answer 49

amount of energy required to remove the outer most e- from an atom in the gaseous state

Question 50

2nd ionization energy

Answer 50

amount of energy to remove a 2nd e-

(lower ionization means want to form positive ions)

Question 51

Electron Affinity (EA)

Answer 51

amount of energy released when an atom in the gaseous state gains an e-

Question 52

electronegativity

Answer 52

the attraction an atom has for a shared pair of e-

Question 53

Ionic radii

Answer 53

positive ion is smaller than its neutral atom

Question 54

Isoelectronic Ions

Answer 54

ions w/ same number of e-

the ion w/ least # of protons will be the largest