Chem one unit 2

electromagnetic waves (photons)

what identified the structure of electrons

visible light

whats one example of electromagnetic radiation

electromagnetic radiation

form of energy that has wave characteristics travels at a speed of 3.00×10^8 m/s

wavelengths and frequencies

electromagnetic radiation has different

Max Plank (wave nature of light)

asserted that energy could be gained or lost in whole number multiples of the quantity hu

Quantum (Plank introduced)

smallest increment of radiant energy that may be absorbed or emitted

Einstein (quantum revolution and examination of electrons with in atoms)

light energy must come in packets

This led to

Photon/ quantum of light (Einstein)

packet of light

light itself

Einstein extended planks idea from energy quanta to…

more (direct correlation)

Larger frequency = blank energy

Less (inverse correlation)

Larger wavelength= blank energy

wavelike behavior

Encounter an obstacle or opening in a barrier that is about the same size, they bend around it.

Diffraction

When waves encounter an obstacle or an opening in a barrier about the same size as the wavelength, they bend around it, this is called

Particle bahvior

When they encounter an obstacle or an opening in a barrier, they are either blocked or pass through a slit.

Constructive interference

waves that interact so that they add to make a larger wave are said to be in phase

in phase

Waves that interact so that they add to make a larger wave are said to be….

Destructive interference

waves that interact so that they cancel each other are said to be out of phase

out of phase

waves that interact so that they cancel each other are said to be…

interference pattern (which supports the behavior of light as wavelike)

the diffraction of light through two slits separated results in a blank

current

the emission of electrons can be determined by measuring a

Photoelectric effect

Electrons are excited and gain kinetic energy

gain so much they are ejected (ionized) from the atoms in metal

Threshold Frequency

No electrons are ejected, no matter how bright the light

binding energy

one photon at the threshold frequency gives the electrin just enough energy for it to escape the atom

more energy

When irradiated with a shorter wavelength photon, electron absorbs…

quantized packet of energy

KE=hv-0 (hv)

photons

Light as particles

classical mechanics

model of the macroscopic world

classical mechanics

deterministic

given exact position and velocities of all particles at a given time one can calculate the future and past positions and velocities of all particles at any time. (trajectory)

Quantum Mechanics

models of the submicroscopic world

quantum mechanics

probabilistic

provides a framework for understanding:

behavior of atoms

periodic trends

chemical bonding

light and subatomic particles

what two things exhibit wave-particle duality

submicroscopic matter

matter extremely small pieces of matter

macroscopic matter

large matter such as a ball

Louis de broglie

Particles could have a wavelike character

wavelength of a particle was inversely proportional to its momentum

Quantum mechanics

atomic model that explains the strange behavior of electrols

Mathematical models (waveforms)

used to explain where in the atom the electrons are housed

visible

400-750nm

Atomic spectroscopy

study of electromagnetic radiation absorbed and emitted by atoms

Niels Bohr (solar system)

electrons move in circular orbits around the nucleus

Bohr’s model

each spectral line is produced when an electron falls from one stable orbit to another of lower energy

electron is promoted to a higher energy level

light is absorbed

energy is emitted

When electron returns to lower state

inconsistent lines=no reproducibility

random/different lines every time

if energy was not quantized we would see

Bohr

electrons occupy permissible places in the atom

probabilty of finding an electron

using mathematical models developed by planck, einstein, Heisenberg, and Schrodinger we can predict….

atomic orbitals (definite sizes and shapes)

probability volumes for electrons

Heisenberg’s work

electron energy and position are complementary

electron with a given energy best we can do is describe a region in the atom of high probability of finding it

Schrodinger’s quantum mechanical model

allows us to calculate probability of finding an electron with a particular amount of energy at a particular location in the atom

quantum numbers (schrodinger)

wave equation yields a set of wave functions/ orbitals and their corresponding energies

Each orbital describes a spatial distribution of electron density

quantum numbers- determine an orbital

n, l, ml

l (orbital type)

angular momentum quantum number

n (energy level)

prinicpal quantum number

ml (position of orbital in an x-y-z plot

magnetic quantum number

ms orientation of the spin

spin quantum number

increase of energy

larger n =

sphere

s orbital

dumbell

p orbital

cloverleaf (dumbell with a donut ring)

d orbital

highly complex multi lobed shapes

f orbital

Aufbau principle

electrons fill lowest available orbitals in the ground state before filling higher

Pauli exclusion principle

no two electrons in an atom may have the same set of four quantum numbers

(NO orbital may have more than two electrons and must have opposite spins)

atomic orbital

described by 3 quantum numbers

electron

described by four quantum numbers

hund’s rule

degenerate orbitals lowest energy is attained when the number of electrons witht he same spin is maximized

degenerate

equal in energy (same n, l)

electron configuraton (fill order)

1s²2s²2p^63s²3p^64s²

noble gas

you can abreviate electron configuration by using the last

quantum number

describes one electron at a time

electron configuration

describes all electron of an atom or ion

Transition metals

these lose s electrons before d electrons

isoelectronic series

ions or atoms with same number of electrons

octet (ns²np²)

ions reach stable configurations at

repulsion between them increases

number of electrons increase

size

strength of interaction increases as the blank of the charges increase

greater attractive force

deeper penetration

effective nuclear charge

total amount of attraction that an electron feels for the nucleus

trends in atomic radii

reactivitly

ionization energy and electron affinity

Zeff explains

increase

Effective nuclear charge …. across a period-size of neutrol atom decreases

Anions

larger then parent atom

Cation

smaller than parent atom

Ionization energy (more energy per electron)

amount of energy required to remove an electron from the ground state of a gaseous atom or ion

increases dramatically (more energy is requitred to remove core electrons)

after all valence electrons have been removed ionization energy

Electron affinity

energy change accompanying the addition of an electron

greater negative value

increasing electron affinity

released

energy is…. when an electron is added

alkali with water is highly exothermic

also produce bright colors when place in a flame

active metals reactions