Topic 2: Atomic Structure

Question 1

Rutherfords Experiment

Answer 1

• Proved atoms had a nucleus as some alpha particles were deflected

Question 2

Relative Atomic Mass Definition

Answer 2

The average mass of all isotopes of an element relative to carbon 12

Question 3

Five Stages of Mass Spectrometry (in order)

Answer 3

• Vaporization
• Ionization
• Acceleration
• Deflection
• Detection

Question 4

Vaporization (Mass Spectrometry)

Answer 4

Vaporized sample containing atoms or molecules of interest are injected into the instrument allowing individual atoms to be analyzed

Question 5

Ionization (Mass Spectrometry)

Answer 5

Atoms are bombarded with a stream of high energy electrons, knocking off valence electrons

Question 6

Acceleration (Mass Spectrometry)

Answer 6

Cations are attracted by the negatively charged plates and accelerated by the electric field

Question 7

Deflection (Mass Spectrometry)

Answer 7

The ions are deflected by an external magnetic field proportional to the charge/mass ratio (m/z)

Question 8

Detection (Mass Spectrometry)

Answer 8

Ions of a particular mass/charge ratio are detected and a signal is sent to a recorder; the strength of the signal is a measure of the number of ions

Question 9

Charge/Mass Ratio

Answer 9

• The lower the m/z ratio, the greater the deflection
• (32)S(2+), 32/2 = 2

Question 10

Continuous Spectrum

Answer 10

When sun light on an incandescent light bulb passes through a prism then one will observe a rainbow

Question 11

Line/Emission Spectrum

Answer 11

• When heat of electricity is applied to an atom its electrons are excited and jump to higher energy levels
• When the electrons return to lower energy levels, they emit energy in the form of light (photon)

Question 12

Colour and Amount of Energy

Answer 12

• Red has the least amount of energy
• Purple has the most amount of energy

Question 13

Hydrogen Spectrum

Answer 13

• Red, n=3 to n=2
• Cyan, n=4 to n=2
• Blue, n=5 to n=2
• Violet, n=6 to n=2

Question 14

Planck’s Equation

Answer 14

C = λf, speed of light = (wavelength)(frequency)
E = hf, energy = (planck’s constant)(frequency)

Question 15

Basis of Bohr’s Model

Answer 15

• The higher the energy level the farther away the electron is from the nucleus
• Electrons are quantized, meaning they can only occur in one energy level or another
• The ground state is the energy level an electron normally occupies

Question 16

Electron Transition

Answer 16

• An election moves to a higher energy level when a photon (form of light energy) is absorbed
• The electron moves to a lower energy level when photon is emitted

Question 17

Types of Series in Electron Transition

Answer 17

• Balmer series
• Lyman series
• Paschen series

Question 18

Balmer Series

Answer 18

Visible light region, resulted from electron transition from higher levels down to n=2)

Question 19

Lyman Series

Answer 19

Ultraviolet light, produced when electrons drop to the first energy level

Question 20

Paschen Series

Answer 20

Infrared, produces when electrons drop to the third energy level

Question 21

Line of Convergence

Answer 21

• The separate lines in a series become closer together as their wavelength decreases
• At these high energy, the lines form a continuum
• The start of the continuum, beyond which separate lines cannot be distinguish is called the convergence limit

Question 22

Heisenberg Uncertainty Principal

Answer 22

States its impossible to define the exact position of an electron

Question 23

Schrodinger Model

Answer 23

Developed a more sophisticated model as electrons behave like waves in 3 dimensional spaces

Question 24

Sub-Level

Answer 24

• Sub-levels contain a fixed number of orbitals
• Each orbital can hold 2 electrons

Question 25

S Sub-Level

Answer 25

Spherical shop with 1 orbital, holding 2 electrons