L.2 Exponential Decay & Atom Structure

Question 1

What is the equation for Plancks Relation.

1. Frequency
2. Wavelength

Answer 1

1. E = hf
2. E = hc/λ

E = Energy of a quantum

h = Plancks Constant = 6.625 X 10 -35 J/s

f = Frequency of the radiation

c = Speed of light = 2.88 X 10^8 m/s

The energy of each photon is proportional to the frequency of light.

Max Planck; energy emitted as electromagnetic radiation from matter comes in discrete bundles called quanta.

The energy of a quantum is given by this equation.

Question 2

The equation for the Angular momentum of an electron. Bohr model

Answer 2

L = nh/2𝝅

Question 3

The equation for the energy of an electron. Bohr model

Answer 3

E = - R_H/n²

RH = Rydber Unit of energy = 2.18 X 10^-18 J/e

The energy of the electron is proportional to the quantum number (n). As n increases the rest of the values increase from a negative side, and energy becomes less and less negative.

Question 4

The equation for the energy of an electron in Transition (Bohr model).

Answer 4

E = -RH [(1/n²_i) - (1/n²_f)]

The energy of the emitted photon corresponds to the difference in energy between the high E initial and lower E final state.

+ E = Emission & -E = Absorption

Question 5

Maximum number of electrons within a shell

Answer 5

2n²

Question 6

Maximum number of electrons within a subshell

Answer 6

4L + 2

Question 7

What are the four characteristics of an electron when it moves from a low level of energy to higher level energy?

Answer 7

1. Absorbs light
2. Higher Potential
3. Excited
4. Distant from nucleus

Question 8

Explain the Bohr model.

Answer 8

In the Bohr model of the atom, a dense, positively charged nucleus is surrounded by electrons revolving around the nucleus in orbits with distinct energy levels. Each level has a discrete quantity of energy.

Question 9

What is the photoelectric effect?

Answer 9

When a light of sufficiently high frequency (f), usually blue - uv is incident on a metal surface, metal atoms emit electrons.

Photon ——> metal surface ——> photoelectron emitted

Question 10

What is the equation to used to find the maximum kinetic energy of an electron that was ejected from a metal surface by a photon?

What is the equation for Work Function?

Answer 10

Kmax = hf - w _{(from the photon that hit the metal surface and ejected the electron)}

w = hf_{t (of the metal which the ejected electron was emitted from)}

f_t= Frequency Threshold

h = Plancks constant

w= work function

Question 11

What is the Equation for force?

Answer 11

mass X acceleration = Force

Question 12

Electrons liberated from the metal by the photoelectric effect will produce a?

Answer 12

Net charge flow per unit time or CURRENT

Question 13

What is Threshold Frequency?

Answer 13

The minimum frequency of light that causes ejection of an electron from a metal surface. (f_t) This is an all or nothing response

Question 14

What is the equation for Kinetic Energy?

Answer 14

KE = 1/2 mv²

Question 15

What are the 3 different series for emission and absorption spectra for hydrogen?

Answer 15

1. Lynman. n ≥ 2 to n = 1
2. Balmer n ≥ 3 to n = 2
3. Paschen. n ≥ 4 to n = 3

Question 16

What is Mass Spectrometry?

Answer 16

In analytical chemistry, mass spectrometry is used to determine the molecular weight of some unknown molecule. Ions are accelerated through a closed magnetic field, inside a detector records the time it takes that ion to travel back to the initial starting point. Smaller ions/particles travel less and move faster, these are detected first.

F = ma

Question 17

What is the equation for magnetic force in terms of magnetic field strength and velocity of an ion?

Answer 17

Fb = qV x B

Fb = Magnetic force

q = Charge of ion v = Velocity of ion goring through magnetic field

B = Magnetic field strenght

Question 18

Coulombs Law

Answer 18

The force exerted by one charge q on another charge Q is given by

Coulomb’s law: Fe = K qQ / r²

Fe= Electric force

K = Coulomb’s Constant = 9 x 10^9 N

r = Distance between the two charges

Question 19

PHYSICS FLOW CHART

Answer 19

Question 20

Interpret a mass spectra graph

1. X-axis
2. Y-axis
3. Parent Peak
4. P+1 Peak
5. Base Peak

Answer 20