ib 7.1 discrete energy and radioactivity

Question 1 Which of the statements is the correct definition of excitation of an electron?

• A When an electron is removed from or added to an atom
• B When an electron moves down an energy level emitting a photon
• C When an electron is given enough energy to move up an energy level, but not enough to leave the atom
• D When an electron is given enough energy to move up an energy level, and sometimes leave the atom

Question 2 The diagram below shows the energy levels of a mercury atom. Which transition produces a photon with longest wavelength?

• A
• B
• C
• D

Question 3 The diagram shows an energy–level diagram for a hydrogen atom. How many discrete photo energies could be produced from these energy levels?

• A 3
• B 5
• C 6
• D 7

Question 4 Which of the following is not a feature of an emission spectrum?

• A When an electron transitions from a higher energy level to a lower energy level, this results in theemissionof a photon
• B An emission spectrum contains a set of discrete wavelengths, represented by coloured lines on a black background
• C An emission spectrum is evidence to show that electrons in atoms can only transition between discrete energy levels
• D An emission spectrum consists of a continuous spectrum containing all the colours with dark lines at certain wavelengths

Question 5 A larger version of the hydrogen emission spectrum from the infrared to the ultraviolet region looks as follows: Using information in the diagram, which hydrogen series corresponds to the highest energy photons being emitted?

• A Lyman series
• B Balmer series
• C Brackett series
• D Pfund series

Question 6 An isotope of (95 241 Am ) undergoes alpha-decay. Which letter on the N-Z graph below represents the correct proton-neutron product of the decay?

• A
• B
• C
• D

Question 7 Uranium−238 undergoes radioactive decay to become Thorium−234. A second decay occurs and the product is protactinium−234. The decay sequence can be represented in equation form, where i, j and k are particles.

• A alpha beta-minus electron anti-neutrino
• B beta-positive beta-minus alpha
• C beta-minus neutron proton
• D alpha beta-positive neutron

Question 8 What are the correct numbers of protons, neutrons, and electrons in a neutral atom of (92 234 U)? protons neutrons electrons

• A 92 92 92
• B 92 142 92
• C 142 92 142
• D 234 142 92

Question 9 What is the charge on, and mass of, an electron neutrino and during what process is an electron neutrino produced? charge/e mass/u production of neutrino

• A +1 zero during β⁺ emission
• B -1 +1 during β⁻ emission
• C zero zero during β⁺ emission
• D zero 0.0005 during β⁻ emission

Question 10 A sample of californium−239 has an activity of 4000 Bq. The half−life of californium−239 is 1 minute. What will the activity be after 4 minutes?

• A 4 000 Bq
• B 1 000 Bq
• C 500 Bq
• D 250 Bq