Exam Q 12

Question 1

What was Boyle’s understanding of the term element?

Answer 1

An element cannot be broken down into a simpler substance

Question 2

Use Bohr’s atomic theory to account for the emission line spectrum of the hydrogen atom

Answer 2

The electron in the hydrogen level occupies fixed energy levels, here it is in the ground state.
The electron can become excited by gaining energy and jump to a higher energy level.
The energy absorbed must be equal to the energy difference between the ground state and the excited state. (E2-E1=hf where E2 is the higher energy level and E1 is the lower energy level, h is Planck’s constant and f is the frequency of light.
The excited state is unstable and the electron falls back down to the ground state emitting a photon of light at a definite frequency as it falls.

Question 3

What colour is observed in a flame test on lithium chloride

Answer 3

crimson

Question 4

Explain, in terms of atomic structure, why different flames colours are observed in flame tests using salts of different metals

Answer 4

Each element has its own unique electron configuration meaning they emit different frequencies of light and that they have their own unique spectra.

Question 5

Define Heisenberg’s uncertainty principle

Answer 5

It states that it is impossible to measure at the same time both the velocity and the position of an electron

Question 5

Describe the testing procedure for flame tests

Answer 5

salt on wooden splints soaked in water for 24 hours,

Place a wooden splint with a salt on it over a flame of a bunsen burner and observe colour of the flame

Question 6

Give one other factor that also contributed to the need for modification of Bohr’s 1913 theory? (other than Heisenberg’s uncertainty principle)

Answer 6

The theory did not account for the wave nature of the electrons
or
didn’t account for sublevels of atoms in spectra

Question 7

Define atomic orbital

Answer 7

it is a region in space where there is a high probability of finding an electron