Chm 2045 Exam 3

Quantum-mechanical model

A model that explains the strange behavior of electrons

Electromagnetic radiation

A type of energy embodied in oscillating electric and magnetic fields

Amplitude

The vertical height of a crest or depth of a trough of a wave

Brightness

What does amplitude of the electric and magnetic field waves determine in light

Wavelength

The distance between any 2 analogous points in a wave

Frequency

The # of cycles that pass thru a stationary point in a given period of time

Frequency equation

speed of light/wavelength

Speed of light

3×10^8 m/s

Electromagnetic spectrum

Includes all wavelengths of electromagnetic radiation

Gamma ray

The form of electromagnetic radiation c the shortest wavelength

X-rays

Has longer wavelengths than gamma rays. Pass thru many substances that block visible light

Ultraviolet radiation

Between x-rays and visible light. The component of sunlight that produces a sunburn

Visible light

Ranging from violet to red

Infrared radiation

The heat you feel when you place your hand near a hot object

Microwaves

Used for radar and in microwave ovens

Radio waves

Used to transmit the signals for forms of communication

X-ray, visible, infrared

Arrange the following types of electromagnetic radiation in order of increasing wavelength: visible, x-ray, infrared

Interference

Waves interact c each other in a characteristic way that cancel each other out or build each other up

Constructive interference

If 2 waves of = amplitude are in phase when they interact and a wave c twice the amplitude results

Destructive interference

If 2 waves are completely out of phase when they interact the waves cancel

Diffraction

When a wave encounters an obstacle or slit that is comparable in size to its wavelength, it bends around it

Photoelectric effect

The observation that many metals emit electrons when light shines upon them

Energy equation

6.626×10^-34 Jxs x frequency

Photon

A packet of light

Energy wavelength equation

(6.626×10^-34 Jxs)speed of light/ wavelength

X-rays,visible,micro

Arrange visible light, x-rays, and microwaves in order of increasing wavelength

Micro,visible,x-ray

Arrange visible light, x-rays, and microwaves in order of increasing frequency

Micro,visible,x-rays

Arrange visible light, x-rays, and microwaves in order of increasing energy per photon

Ultraviolet

Which type of electromagnetic radiation has the higher energy per photon UV or infrared

Binding energy of emitted electron equation

(6.626×10^-34)frequency

Kinetic energy equation

(6.626×10^-34)frequency-binding energy of emitted electron

Emission spectrum

Separating the light emitted by a single element in a glass tube into its constituent wavelengths by passing it thru a prism

de Broglie relation

wavelength=(6.626×10^-34)/massxvelocity

Complementary properties

Exclude one another- the more we know about 1, the less we know about the other

Heisenberg’s uncertainty principle

(Uncertainty in the position)xmassx(uncertainty in the velocity)>or=(6.626×10^-34)/4pi

Deterministic

The present determines the future

Interderminacy

If an electron were thrown from the pitcher’s mound to home plate, it would land in a diff place every time, even if it were thrown in exactly the same way

Orbital

A probability distribution map showing where the electron is likely to be found

Wave function

A mathematical function that describes the wavelike nature of the electron

Quantum numbers

4 interrelated #s that determine the shape and energy of orbitals, as specified by a solution of the schrodinger equation

Principal quantum number

An integer that specifies the overall size and energy of an orbital. The higher the quantum # n, the greater the avg distance between the electron’ and the nucleus and the higher its energy

Angular momentum quantum number

An integer that determines the shape of an orbital

Magnetic quantum number

An integer that specifies the orientation of an orbital

n

The principal quantum #

l

The angular momentum quantum #

m_l

The magnetic quantum #

Rydberg constant for hydrogen

2.18×10^-18

-2,-1,0,1,2

What values of m_l are possible for l=2

Principal level

The group of orbitals c the same value of n

Sublevel

Those orbitals in the same principal lvl c the same value of n and l

Wavelength of a photon equation

((6.626×10^-34)(speed of light))/energy

Probability density equation

Probability/unit volume

Radial distribution function

A mathematical function that represents the total probability of finding an electron within a thin spherical shell at a distance r from the nucleus

Total radial probability

(probability/unit volume)xvolume of shell @ r

1 pm

10^-12 m

Node

A point where the wave function, and therefore the probability density and radial distribution function, all go thru 0

Phase

The neg or pos sign of a wave

1nm,10nm,1mm,10mm

Organize the wavelengths of light 10nm,10mm,1nm,1mm from highest frequency to lowest

Gamma rays

Which kind of electromagnetic radiation contains the greatest energy per photon microwaves, gamma rays, infrared, or visible light

False

TorF Increasing the brightness of incoming light increases the kinetic energy of the ejected electrons

False

TorF Increasing the wavelength of incoming light increases the kinetic energy of the ejected electrons

True

TorF Increasing the brightness of incoming light increases the # of ejected electrons

True

TorF Increasing the frequency of incoming light can increase the # of ejected electrons

Periodic property

A property of an element that is predictable based on an element’s position in the periodic table

Electron configuration

For an atom shows the particular orbitals that electrons occupy for that atom

Ground state

The lowest energy state

Orbital diagram

Symbolizes the electron as an arrow and the orbital as a box

Pauli exclusion principle

No 2 electrons in an atom can have the same 4 quantum #s

Degenerate

A term describing 2 or more electron orbitals c the same value of n that have the same energy

Coulomb’s law

The potential energy of 2 charged particles depends on their charges and on their seperation

Potential energy equation

(1/4piE_0)(q_1q_2/r)

E_0

8.85×10^-12C²/Jm

Decreases

According to coulomb’s law, what happens to the potential energy of 2 oppositely charged particles as they get closer together does it increase or decrease

Shielding

The effect of an electron of repulsion by electrons in lower-energy orbitals that screen it from the full effects of nuclear charge

Effective nuclear charge

The actual nuclear charge exp by an electron, defined as the charge of the nucleus + the charge of the shielding electrons

Penetration

The phenomenon of some higher-lvl atomic orbitals having significant amts of probability within the space occupied by orbitals of lower energy lvl

Aufbau principle

The principle that indicates the pattern of orbital filling in an atom

Hund’s rule

When filling Degenerate orbitals, electrons fill them singly 1st, c parallel spins

Valence electrons

Important in chm bonding and in main-group elements, they are those that are in the outermost principal energy lvl

Core electrons

The electrons that are not the valence electrons

Nonbonding atomic radius

When an element is frozen into a solid in which the atoms are not touching each other, but are not bonded together. The distance between the centers of the adjacent atom is then twice the radius of that atom

Van DER Waals radius

Represents the radius of an atom when it is not bonded to another atom

Covalent radius

Another way to define the size of an atom and differs for nonmetals and metals

Atomic radius

Refers to a set of avg bonding radii determined from measurements on a L # of elements and compounds

Increases, decreases

The general strands in the atomic radii of main group elements states that as we move down a column atomic radius ____. And as we move to the right across a period atomic radius ____.

Effective nuclear charge equation

(Actual nuclear charge)-(charge screened by other electrons)