Chapter 3 - Electrons in the Atom

Question 1

Emission line spectrum

Answer 1

Lines emitted when an electric current is passed through hydrogen

Question 2

Spectrometer

Answer 2

Carry out measurements on spectra

Question 3

Spectroscope

Answer 3

Used to observe spectra

Question 4

Quantum of energy

Answer 4

The fixed amount of energy an electron in an atom may have

Question 5

Quantisation

Answer 5

The energy of an electron in an atom has specific values

Question 6

Spectroscopic evidence for the existence of energy levels

Answer 6

• Electrons in one energy level have a fixed amount of energy
• Energy levels are n
• As long as an electron is in one energy level, it neither gains nor loses energy

Question 7

Ground state

Answer 7

• Atoms normally exist in the ground state because they have the lowest energy levels
• When am atom is provided with energy (electricity or heating) it jumps

Question 8

Excited state

Answer 8

• E2 - E1 =
• Electrons in excited state are unstable and fall back down
• Excess energy is released in a photon of light
• Light is given off at different frequencies

Question 9

Frequency of light emitted

Answer 9

• The amount of energy emitted appears as a particular-colored line on the emission spectrum
• Each line appears as electrons are moving and falling
• Each element has a different number and arrangement of electrons

Question 10

Bohr’s experimental work

Answer 10

• Calculated the frequency and wavelength of the colored lines
• Calculated wavelengths using spectrometer which equaled the one he calculated mathematically

Question 11

Why is there many electron transitions in hydrogen

Answer 11

• There are millions of atoms of hydrogen in a sample

* Not all atoms receive the same amount of energy

Question 12

How to see electron transitions

Answer 12

Fluorescent light strips

Lasers

Question 13

Sodium

Answer 13

Yellow

Question 14

Potassium

Answer 14

Lilac

Question 15

Strontium

Answer 15

Red

Question 16

Barium

Answer 16

Green

Question 17

Copper

Answer 17

Blue-green

Question 18

Why different elements produce different colors

Answer 18

Each element has a different number and arrangements of electrons
Different electron transitions
Different frequencies of light

Question 19

Why does spectra have different lines

Answer 19

• Each electron occupies a fixed energy level
• When electrons occupy energy, it moves up to a higher level (excited state)
• Falls down, gives off a definite frequency of light
• E2 - E1=hf
• Definite amounts emitted = electrons occupy definite frequencies of light

Question 20

Atomic Absorption Spectrometry

Answer 20

• Dark lines against a colored background
• White light passed though a gas
• Light that comes out of passed through a prism with certain wavelengths missing
• Wavelengths are absorbed by the sample
• Atoms in the ground state absorb the same radiations as they emit in the excited state

Question 21

Uses of AAS

Answer 21

• Detecting the presence of certain elements in materials dissolved in water and measuring their concentrations
• Analysis of water for heavy metals
• Measuring the concentration of lead in blood

Question 22

S
P
D
F

Answer 22

Sharp
Principal
Diffuse
Fundamental

Question 23

Limitations of Bohr Theory

Answer 23

• Failed to account for many of the lines in the emission spectra of the atoms
• Did not take into account that the electrons had a waves motion
• In conflict with Heisenberg’s Uncertainty Principle
• Did not take into account the presence of sub levels

Question 24

Erwin Schrödinger

Answer 24

Worked out probability of finding an electron in an atom

Question 25

S orbital

Answer 25

Spherical

Question 26

P orbital

Answer 26

Dumbbell

Px, Py, Pz