Chapter 5 Chemistry

-1924-Louis de Broglie, a French grad. student, aced the question:

"Given that light behaves as waves and particles, can particles of matter behave as waves? -Wavelike behavior of matter=matter waves

-Bohr applied....... -In the Bohr model, the lone electron in the hydrogen atom can have only________

-quantum theory to electron energy levels in atoms to explain the atomic emission spectrum of hydrogen. -certain specific energies

-Different atomic orbitals are emoted by letters.

-s: spherical -p-dumbbell shaped

******need to know order. which has higher energy/frequency

...

Atomic absorption spectrum:

...

NEED TO KNOW ORBITALS

...

ORDER OF ELECTRON ORBITAL FILLING

...

REVIEW PIC ON PAGE 133 WITH THE CIRCLES

...

Principle quantum numbers:

1,2,3,4,

Limitations of Rutherford's atomic model:

1. It could not explain the chemical properties of elements Ex: Model could not explain why metals or compounds of metals gave off characteristic colors when heated in a flame. 2. Could not explain why an object such as an iron scroll glows dull red, them yellow, and then white when heated to lighter and higher temperatures.

electron configurations can be written using the : (3)

1. aufbau principle 2. Pauli exclusion principle 3. Hund's rule

-Electromagnetic Radiation list:

1. radio waves 2. microwaves 3. infrared waves 4. visible light 5. ultraviolet waves 6. X-rays 7. gamma rays.

s-orbitals/max electrons

1/2

p-orbitals/max electrons

3/6

d-orbitals/max electrons

5/10

f-orbitals/max electrons

7/14

*What did Bohr propose in his model of the atom?

Bohr proposed hat an electron is found only in specific circular paths, or orbits, around the nucleus.

*How does quantum mechanics differ from classical mechanics?

Classical mechanics adequately describes the motions of bodies much larger than atoms, while quantum mechanics describes the motions of subatomic particles and atoms as waves.

-Plank's Constant:

Constant h has a value of (6.626)(10-34 J's)

-The energy of photons is quantized according to the equation:

E=hv

*How do sub-levels of principle energy levels differ.

Each energy sub level corresponds to one or more orbitals of different shapes. The orbitals describe where an electron is likely to be found.

-Light consists of ______________

Electromagnetic waves

-Photoelectric effect:

Electron are ejected when light shines on metal Ex: red light will not cause potassium to eject electrons, but very weak yellow light shining on potassium will begin the effect.

Hund's Rule-

Electrons occupy orbitals of the same energy in a way that makes the number of electrons the same spin direction as arge as possible -Each orbital will not double up until each has at least one electron on the level

-Hund's Rule:

Electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible. Ex: three electrons would occupy three orbitals of energy???

Aufbau Principle

Electrons occupy the lowest energy level first

-Electronic transition:

Emission occurs: a quantum of energy in the form of light is emitted when the electron drops back to a lower energy level.

What type of radiation has the lowest frequency? Highest?

Lowest-radio waves/ highest-gamma rays

-Ultraviolet:

Lyman series-lines due to the transition of electrons from higher energy levels to the lowest energy level n=1.

-Quantum Mechanical Model:

Modern description of the electrons in atoms came from the mathematical solutions of the Schrödinger equation.

ROYGBIV

Red Orange Yellow Green Blue Indigo Violet These tools can be used to identify an element low --> high energy

After discovering the atomic nucleus _________ used existing ideas about the atom and proposed an atomic model in which the electrons move around the nucleus like the planets move around the sun.

Rutherford

-Hertz(Hz):

SI unit of cycles per second( s-1)

-Energy levels:

The fixed energies an electron can have.

*How are the frequencies of light emitted by an atom related to the changes of electron energies?

The light emitted by an electron moving from a higher to a lower energy level has a frequency erectly proportional to the energy change of the electron.

*What does the quantum mechanical model determine about the electrons in an atom?

The quantum mechanical model determines the allowed energies n electron can have and how limey it is to find the electron in various locations around the nucleus of an atom.

In an electron configuration, what does a superscript stand for?

The superscript stands for the number of electrons occupying a given sub-level

-Atomic emission spectrum:

The wavelengths of the spectral lines are characteristic of the element, and they make up the atomic emission spectrum of the element.

-Electron configurations:

The ways in which electrons are arranged in various orbitals around the nuclei of atoms

*What are the three rules for writing electron configurations of elements?

Three rules- 1.the aufbau principle 2. the Pauli exclusion principle 3. Hund's rule- tell you how to find the electron configuration of atoms.

*How did Einstein explain the photoelectric effect?

To explain the photoelectric effect, Einstein proposed that light could be described as a quanta of energy that behave as if they were particles.

-Ground state:

When an electron has it's lowest possible energy, the atom is in it's ground state. -Principle quantum number(n)=1 -Excitation of the electron by absorbing energy:2,3,4,5,+6 etc.

*What causes atomic emission spectra?

When atoms absorb energy, their electrons move to higher energy levels. These electrons loose energy by emitting light when they return to lower energy levels.

-Spectrum:

When sunlight passes through a prism, the different wave lengths separate into a spectrum of colors. Ex: Rainbow

-Quantum:

a quantum of energy is the amount of energy required to move an electron from one energy level to another energy level. The energy for an electron is therefore said to be quantized.

blue-

absorb light

-Visible spectrum:

almer series-result from transitions from higher energy levels to n=2

-Pauli Exclusion Principle:

an atomic orbital my describe at most two electrons Ex: either one of two electrons can occupy an s orbital or a p orbital. To occupy the same orbital the, two electrons must have opposite spins; electron spins must be paired.

The number and arrangements of electrons gives....

an elements it's chemical compounds

-No two elements have the same _______

atomic admission spectrum

Passing the light emitted by an element through a prism gives the _______ of the element

atomic emission spectrum

For each energy levels the Schrödinger equation also leads to a mathematical expression, called an __________, describing the probability of finding an electron at various locations around the nucleus. Represented pictorially as a region of space in which there is a high probability of finding an electron.

atomic orbital

the atoms of different elements are different with regard to...

chemicals and physical properties

________ describes the motion of large bodies

classical mechanics

The product of frequency and wave length equals a ___________, the speed of light

constant

the product of wavelength and frequency equals a _____ the speed of light

constant

-Atomic emission spectrum of an element is ____________

continuous.

one full wave is a _____

cycle

****Number and arrangement of Electrons...

determines chemical properties of an element

-In 1926 the Austrian Physicist Erwin Schrödinger (1887-1961) used these calculations are results to....

devise and solve a mathematical equation describing the behavior of the electron in a hydrogen atom.

isotopes:

different versions of elements. same number of proton. different number of neutrons

example of animal w/ high frequency sound:

dolphins/bats

The ways in which electrons are arranged into orbitals around the nuclei of atoms are called:

electron configuration

-Aufbau Principle:

electrons occupy the orbitals of lowest energy first. The orbitals of any sub level of a principle energy level are always of equal energy s-lowest energy sub-level

red-

emit light

-when an electron falls back down from the excited state (Back)to the ground state it emits__________

energy as light

When atoms absorb energy, their electrons move to higher _____

energy levels

what are the fixed energies of electrons called?

energy levels

In electron configurations, what does the sum of the superscript equal?

equals the number of electrons in the atom

t/f: Every element in the periodic table follows the aufbau principle?

false

t/f: The emission spectrum of an element can be the same as the emission spectrum of another element.

false

t/f: the electrons in an atom can exist between energy levels?

false

Half-filled levels are not as stable as _______ levels, but are more stable than other configuration

filled

-Spectral lines:

for the transitions rom higher energy levels to n=4 and n=5 also exist

-Max Planck:

found that he could explain the color changes if he assumed that the energy of a body changes only in small desecrate units, or quanta. -----Plank showed mathematically that the amount of radiant energy (E) of a single quantum absorbed by a body is proportional to the frequency of radiation

when an electron drops to a lower energy level, it emts light that has a ____ directly proportional to the energy change of the electron

frequency

-Werner Heisenberg:

german physicist-examined another feature of quantum physics.

what is the lowest possible energy of an electron called?

ground state

You can add energy by _________

heat/electricity lightning

high energy-_________

high frequency

Only electrons moving from _____ to _____ energy levels lose energy and emit light

higher(excited).....lower(ground)

-RELATIVE ABUNDANCE-

how many types of isotopes

the wavelength of light _______ the frequency ____________

increases.......decreases

-Spin:

is a quantum mechanical property of electrons and may be thought of as a clockwise or counterclockwise.

Photons:

light quanta

Long wavelength -

low energy-low frequency

-A small energy change involves the emission or absorption of _____________. A large energy change envelopes the mission of absorption of ___________

low-frequency radiation...... high frequency radiation.

Bohr: he created the idea that everything had a _______

made a revised model which made it easier to do the things the original model could not. "energy level" or fixed energy

The atomic number tells me how.....

many electrons/protons there are

-All the photons in a beam of ______________(light with one frequency) have the same energy. If the frequency is too low then electrons won't be emitted.

monochromatic light

a quantum of energy...

moves an electron from its present energy level to a higher one

-In 1913 Niels Bohr (1885-1962), a young Danish physicist and student of Rutherford, developed a new atomic model. -He changed Rutherford's model to incorporate.....

new discoveries about how the energy of an atom changes when the atom absorbs or emits light. He considered hydrogen(simplest atom) which has 1 electron.

does the heinsenburg uncertainty principle apply to cars and airplanes?

no, only to small particles

-Aptitude:

of a wave is the wave's hight from zero to the crest . weird tepee symbol

Pauli Exclusion Principle

only two electrons in each atomic orbital

Often though as a region of space in which there is a high probability of finding an electron

orbital

Bohr proposed that an electron is found only in specific circular paths, or _____ around the nucleus

orbiting

*Only if the frequency of light is above the threshold frequency will the ______________

photoelectric effect occur

what did albert einstein call the quanta of light energy?

photon

term that is used to label the energy levels of electrons:

principle quantum numbers

describing light as ______ of energy that behave as particles helps to explain the photoelectric effect

quanta

The ______ describes the energy an electron ca have and the probability if finding the electron in various locations around the nucleus of an atom

quantum mechanics

____ describes th emotion of very small particles, such as subatomic particles

quantum mechanics

-The newer theory is called __________ and the older theory is called _________

quantum mechanics.....classical mechanics

No two elements have the same ___________ the atomic structure will be different this will determine the type of energy that is

quantum number......absorbed or released

What kinds of invisible and visible radiation are included in the electromagnetic spectrum?

radio waves/microwaves/infrared/visible light/ultraviolet waves/ x-ray/ gamma rays

Wavelength:

represented by is the distance between the crests .Rep. by V

-Frequency:

represented by is the number of wave cycles to pass a given point per unit of time. Units of frequency are usually cycles per second.

when sunlight passes through a prism, the different wavelengths separate into a ______ of colors

spectrum

Filled energy sub levels are more _____ than partially filled sub-levels

stable

-Heisenberg uncertainty principle:

states that it is impossible to know both the VELOCITY and POSITION of a particle at the same time. Critical when dealing with electrons, but does not matter with ordinary things like cars.

orbitals, which are found in ____, have different shapes, depending on the energy of the electrons they contain

sublevels

what happens when an electric current is passed through the gas or vapor of an element?

the element emits light as it is excited by the passage of electric discharge-atoms absorb energy and emit light

Difference between the previous models of the atom and the modern quantum mechanical model?

the quantum mechanical model takes into account the wave of the electron to the probability of location

Atomic Absorption Spectrum-

the wavelengths of light are absorbed

Atomic Emission Spectrum-

the wavelengths of light are reemitted

-Each spectral line in an atomic emissions spectrum of an element corresponds....

to exactly one wavelength of light emitted by the electrons of that element.

-Paschen series:

transitions to n=3 from higher energy levels produce the paschen series-(infrared range?)

t/f: Quantum mechanics describes the motions of subatomic particles and atoms as waves.

true

t/f: The quantum mechanical model of the atom estimates the probability of finding an electron in a certain position?

true

t/f: the wavelength and frequency of light are inversely proportional?

true

-1905; Albert Einstein, patent examiner in Bern, Switzerland, .....

used Plank's quantum theory to explain the photoelectric effect. Light behaves as a stream of particles- explains photoelectric effect

according to the heinsenburg uncertainty principle, it is impossible to know exactly both the ____ and the ______ of a particle at the same time

velocity......position

Atomic Emission spectrum:

very unique for an element-like a finger print-used to identify elements

orbital diagram-

visual representation of the location of the electrons in an element 1- Each orbital represented by a circle or square 2- Each electron is represented by an arrow 3- direction of the arrow indicates spin

energy is always a _______

wave

The distance between one crest and another is the ______-

wavelength -length of one energy cycle

Example of animal with a low frequency sound:

whale

-Isaac Newton (1964-1727) tried to explain:

what was known about the behavior of light by assuming that light consists of particles. -By the 1900s there was enough evidence to convince scientists that light consists of waves.