1. Give the number of protons, neutrons, and electrons in the following atoms or ions:

2. The following table shows the number of protons, electrons, and neutrons in a series of atoms and ions.

a) Which symbols represent isotopes?

b) Which symbols represent positive ions?

3. Chromium has four naturally occurring isotopes, and their masses and natural abundances are shown in the

table below. Calculate the relative atomic mass of chromium to two decimal places.

4. Indium has two naturally occurring isotopes: Indium- 113 and indium-115. The relative atomic mass of

indium is 114.82. Calculate the natural abundance of each isotope.

5. Arrange the following ions in terms of how much they will be deflected in a mass spectrometer (the one that

will be deflected most first):

CDO IB Chemistry SL Unit 3 Review

6. What are the electronic arrangement of the following atoms?

C Si Cl Ca2+

7. Arrange the following in order of :

a) Increasingly energy

b) Decreasing wavelength

Ultraviolet radiation

Infrared radiation

Microwaves

Orange light

Green light

8. Describe how a line in the Lyman series of the hydrogen atom spectrum arises.

9. Draw an energy level diagram showing the first four energy levels in a hydrogen atom and mark with an

arrow on this diagram one electronic transition that would give rise to:

a) a line in the ultraviolet region of the spectrum

b) a line in the visible region of the spectrum

c) a line in the infrared region of the spectrum

Exam Style Questions

10. Which of the following contains 50 neutrons?

11. Which of the following will be deflected least in a mass spectrometer?

12. Which of the following has more electrons than neutrons?

13. Rhenium has two naturally occurring isotopes, Re – 185 and Re - 187. The relative atomic mass of

rhenium is 186.2. What is the natural abundance of these isotopes?

14. Which of the following electronic transitions in the hydrogen atom will be the highest energy?

a. n = 8 → n = 4

b. n = 9 → n = 3

c. n = 7 → n = 2

d. n = 6 → n = 2

15. a) Define the terms atomic number and isotopes of an element.

b) State the number of protons, neutrons and electrons in an atom of

c) A sample of iron from a meteorite is analyzed in a mass spectrometer.

[i] State the order in which the stages occur in the operation of a mass spectrometer.

[ii] Explain what happens at each stage in the operation of a mass spectrometer.

[iii] The following results were obtained from the analysis of the iron:

Calculate the relative atomic mass of this sample, giving your answer to two decimal places.

16. a) Describe the difference between a continuous spectrum and a line spectrum

b) Sketch a diagram of the emission spectrum of hydrogen in the visible region, showing clearly the relative

energies of any lines

c) Explain how a line in the visible emission spectrum of hydrogen arises.