3. Arrangement Of Electrons

Question 1

Bohr passed light from a _______ through a prism to emit an emission spectrum.

Answer 1

Hydrogen Gas Discharge Tube

Question 2

Spectrometers

Answer 2

Allow measurement of the frequency of each band of light

Question 3

Spectroscopes

Answer 3

Allow the spectrum to be viewed only, not measured

Question 4

Lithium flame test colour

Answer 4

Crimson

Question 5

Potassium colour flame test

Answer 5

Lilac

Question 6

Barium colour flame test

Answer 6

Green

Question 7

Sodium (street lights) colour

Answer 7

Yellow

Question 8

Energy level

Answer 8

Energy level is defined as the fixed energy value that an electron in an atom may have

Question 9

Ground state

Answer 9

Ground state of an atom is one in which the electrons occupy the lowest available energy levels.

Question 10

Excited state

Answer 10

Excited state of an atom is one in which the electrons occupy higher energy levels than those available in the ground state.

Question 11

What is the name given to the visible light emitted in the emission spectrum?

Answer 11

Balmer Series: emission of visible light due to electrons falling to the n=2 energy level.

Question 12

Why do different elements have different line spectra?

Answer 12

• Diff no. Of electrons
• Diff. Nuclear charge
• Diff electrostatic attractions resulting in diff. Electron transitions

Question 13

Formula for emission spectrum

Answer 13

E2 - E1 = hf

H is Planck’s constant

Question 14

Uses of an Atomic Absorption Spectrometer

Answer 14

Detecting presence and concentration of certain elements (lead, chlorine) dissolved in water.

Question 15

Sublevel

Answer 15

Sublevel is a subdivision of a main energy level and consists of one or more orbitals of the same energy.

Question 16

Who proposed the theory of electrons having a wave motion?

Answer 16

De Broglie

Question 17

Heisenberg’s Uncertainty Principle

Answer 17

States that it is impossible to measure the velocity and position of an electron simultaneously .

Question 18

3 limitations of Bohr’s theory

Answer 18

• only accounted for the emission spectrum of Hydrogen (simple case)
• didn’t take wave particle duality of electrons into account (el travel in precise paths)
• didn’t take existence of sublevels/orbitals into account
• Heisenberg in conflict w Bohr: can only refer to probability of an electron

Question 19

Atomic orbital

Answer 19

A region in space around the nucleus where there is a high probability of finding an electron.