Quantum Theory & Electronic Structure of Atoms Chap 3

General honors Chemistry

Kinetic Energy

Def: Movement of an object due to its mass and velocity.

KE = 1/2 mu²

The M in KE = 1/2 mu²

Mass

The U in KE = 1/2 mu²

Velocity

Thermal Energy

The energy from random motion of atoms and molecules

Potential Energy

energy possessed by an object by the virtue of its position

2 Forms of Potential Energy

Chemical Energy and Electrostatic Energy

Chemical Energy

potential energy stored within the structural units of chemical substances

Electrostatic Energy

potential energy resulting from interaction of charged particles

Opposite charged particles

Attract to each other

Similar charged particles

Repel from each other

The magnitude of the resulting electrostatic potential energy

is proportional to the product of two charges divided by distance between them

Electrostatic Energy Equation

Eₑₗ α Q1Q2/d

If q1q2 are opposite

Eₑₗ is negative indicating attraction

If q1q2 are like charges

Eₑₗ is positive indicating repulsion

Law of Conservation of Energy

When one form of energy disappears the same amount of energy must appear in another form/s

SI unit that means a small quantity of energy

J (joules)

Kinetic Energy in a single Joule

½ (2kg)(1m/s)²

½ (2kg)(1m/s)² can also equal

1kg x 1m²/s²

N in Nm

Newton

1 Joule can also equal

1 Nm

1N can also equal

1 kg m/s²

1000 Joule

1 kJ

Proportionality constant (α) can also be written as

C

Gamma Rays nm and Hz

nm 10^-3

Hz 10²⁰

Xray nm and Hz

nm 10^-1

Hz 10¹⁸

Ultraviolet nm and Hz

nm 10

Hz 10¹⁶

Visible Light nm and Hz

nm 10³

Hz 10¹⁴

Infrared nm and Hz (less than ___ more than Visible Light)

nm 10⁵

Hz 10¹²

Microwave nm and Hz

nm 10⁷

Hz 10¹⁰

Radio waves nm and Hz

nm 10¹¹

Hz 10⁶

Wavelength (λ)

distance between two identical points on successive waves

Frequency (v)

nu, number of waves that pass through a particular point in 1 second

Amplitude

vertical distance from the midline of a wave to the top of the peak or the bottom of the trough

The Speed of Light represented by

C

The Speed of Light formula

3.00 × 10⁸ m/s

Speed, Wavelength and Frequency Formula

c = (λ)(v)

What are (λ)(v) expressed by

meters and reciprocal seconds ^-1

What unit of measurement do visible wvlnghts use

Nanometers (nm or 10^-9)

What are the units of measurements does microwave and x ray use

Centimeters (cm or 10^-2)

Electromagnetic waves has a(n)____ component and ____ component which have the

_______ wavelenght and frequency, therefore _______ speed

1) electric field 2) magnetic field component 3) same 4) same

Double Slit Experiment (concept)

light passed through two slits shot out a series of light and dark lines rather than only two bright lights

Constructively

the waves are in phase (bright light lines in double slit experiment)

Destructively

the waves are out of phase (dark lines in double slit experiment)

wavelength / frequency relationship (concept)

The wavelength and frequency of light are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength.

wavelength / energy relationship (concept)

Simple answer: as the wavelength gets shorter, the energy increases; as the wavelength gets longer, the energy decreases.

frequency / energy relationship (concept)

The greater the energy, the larger the frequency and the shorter (smaller) the wavelength. Given the relationship between wavelength and frequency — the higher the frequency, the shorter the wavelength — it follows that short wavelengths are more energetic than long wavelengths.

Quantum Theory (concept)

Planck proposes that radiant energy can be emitted/absorbed in discrete quantities in the form of electromagnetic radiation called a quantum

Energy of a single quantum formula

E=hv

The (h) in E=hv

H is Planck’s constant (6.63×10^-34(J)(s))

What is Planck’s constant

(6.63×10^-34(J)(s))

Energy is _____ not _____

quantized not continous

Photoelectric Effect

electrons ejected from surface of metal exposed to light

Threshold frequency

how much light/energy is needed to eject electons

Photons

Particles of Light

Equation of photon energy

E_photon=hv

H in E_photon=hv

Planck’s constant

V in E_photon=hv

frequency

Work function (definition)

amount of energy that it takes to knock out electrons

W in hv=E_k+W

Work function

If photon frequency equals the threshold

it will dislodge the loosest electron

If the photon frequency is above the threshold

it will knock out electron and put some more kinetic energy to ejected electron

Emission spectra

emission spectrum can be seen by energizing a sample with thermal or another form of energy

Rydberg’s equation

1/λ =R_infinity (1 /n^2₁ - 1 /n²₂)

R_infinity is

Rydberg’s constant

n₁ and n₂ are

positive integars, where n₂ > n₁