ch 301 exam 1

radiowaves

• lowest energy and frequency, longest wavelength

• excite spin nucleus

  • ex: MRI

microwaves

• excite spin of electrons

  • ex: cook food (causes fats/water to rotate)

infared (IR)

• causes molecules vibrate

  • ex: night vision goggles, sorting recycle materials

visible light/ultraviolet (UV)

• causes spin of outer electrons

  • ex: UV-VIS spectroscopy, causes UV burns

x-rays

• causes spin of core/inner electrons

  • ex: medical imaging — causes cell mutation

gamma rays

• highest energy and frequency, shortest wavelength

• decay of nucleus

  • ex: cosmic radiation emitted by stars

as energy increases, wavelength _____ and frequency ______.

decreases (gets shorter), increases

E photon (hv) is greater than work function (phi)…

electron ejected

E photon (hv) is less than work function (phi)…

electron NOT ejected

absorption

electron moves UP energy levels

• ex: n=2 to n=3

emission

electron goes DOWN energy level

• ex: n=2 to n=1

aufbau principle

fill lower energy level before moving onto high energy level

hund’s rule

singly fill all orbital with one electron first before pairing up

pauli exclusion principle

only one set of quantum numbers for each electron

energy increases…

further away from nucleus

fall to n=1

UV range -- LYMAN SERIES

fall to n=2

visible range -- BALMER SERIES

fall to n=3

IR range -- PACHMAN SERIES

electronegativity

• increases going up and to the right

• decreases going down and to the left

ionization energy

• increases going up and to the right

• decreases going down and to the left

atomic radius

• increases going down and to the left

• decreases going up and to the right

ionic radius

more protons = smaller radius

group 1

alkali metals

group 2

alkaline earth metals

group 7

halogens

group 8

noble gases

n

• principal quantum number

• determines ENERGY and SIZE

l

• angular quantum number

• determines SHAPE

ml

• magnetic quantum number

• determines ORIENTATION

ms

• magnetic spin quantum number

• determines SPIN

l=0

s

l=1

p

l=2

d

l=3

f

chromium exception

4s1 3d5

copper exception

4s1 3d10

ionization energy exception

group 14,16,15

least IE —- 14<16<15 —-- most IE

rydberg equation

how much light is emitted/absorbed as electron moves between energy levels

deBrogile equation

light can behave as both a wave and a particle

• when wavelength decreases, mass and velocity increase

• heavier particles have shorter wavelengths -- INVERSE RELATIONSHIP

shielding

reduction of effective nuclear charge experienced by valence electron due to the REPULSIVE effect of inner shell electrons

-- inner electrons shield the valence electrons from the nucleus

bigger the atom…

lower ionization energy

Zeff formula

Zeff (effective nuclear charge) = Z (protons) - S (number of inner electrons)

the smaller an atom is…

harder to remove an electron from it

number of neutrons

mass - protons

atomic radius (largest)

• bottom-left

  • Fr

atomic radius (smallest)

• top-right

  • F

why do atoms in group 16 have lower ionization energies than atoms in group 15?

there are REPULSIVE effects between paired electrons in 2p orbitals

electronegativity of H

2.1

electronegativity of Li

1

electronegativity of Be

1.5

electronegativity of B

2

electronegativity of C

2.5

electronegativity of N

3

electronegativity of O

3.5

electronegativity of F

4

shielding effect

caused by the inner shell electrons, which reduce nuclear attraction experience by outer electrons

• stays constant left to right

• increases up and down

effective nuclear charge

• increases left to right

• increases as it goes down