1. Atomic Structure Review

2. How many Electrons does Chlorine (Cl) have?
How many Neutrons does Chlorine (Cl) have?
How many Protons does Chlorine (Cl) have?

3. Who proposed electrons travel around the nucleus of an atom in definite paths or “orbits”?

4. Who stated the atom was “neutral” in charge
Who stated the atom was “neutral” in charge? (Hint: He experimented using a “Cathode Ray Tube”)

5. What do you call atoms of the same element which contain different numbers of neutrons?

6. Which particle in the atom has a positive charge?

7. Who proposed the Law of Conservation of Mass or Matter?
Explain what this law states.

8. In the isotope Iron-53
How many Protons?
How many Electrons
How many Neutrons?

9. What is the Atomic Number of Neon (Ne)?

10. An element is defined by its number of ____. a. Protons b. Neutrons c
An element is defined by its number of ____? a. Protons b. Neutrons c. Electrons

11. The Mass Number of an atom is the number of _________ plus the number of ________.

12. The element Gold (Au).
Number of Protons
Number of Electrons
Number of Neutrons

13. Which scientist fired alpha particles at Gold foil and concluded the atom consisted of a small, dense, positive core he called a nucleus?

14. Who is considered “The Father of Modern Chemistry”?

15. To determine the number of neutrons in an atom you can subtract the number of ________ from the Atomic Mass number.

16. The sub-atomic particle of the atom with a “negligible” mass is ________. Its mass is so small it is ignored when determining the mass of the atom.

17. The unit a.m.u. stands for _______.

18. Cobalt (Co) has two isotopes: Cobalt-58 and Cobalt-60
Cobalt (Co) has two isotopes: Cobalt-58 and Cobalt-60. Which isotope contains the greatest number of Protons?

19. What is the electrical charge on an Electron?

20. If you know the Atomic Number of a neutral atom you know what other 3 things?

21. What 2 sub-atomic particles are located in the Nucleus of an atom?

22. Which scientist who in 1803 proposed an Atomic Theory which states all substances are composed of atoms which cannot be created, divided, or destroyed?

23. Which scientist is credited with the discovery of the Neutron?

24. What is the only element which does not contain a Neutron?

25. Which neutral atom contains 93 electrons?

26. If I subtract the Atomic number of Silver (Ag) from the Atomic Mass of Iron (Fe), I would get a number equal to the number of protons of what element?

27. What are the only two elements which occur as liquids at room temperature?

28. Which scientist is associated with the “Electron Cloud” theory of electrons?

29. Which scientist was 1st to prove an atom can be divided into smaller parts?

30. What is the element which contains 82 Protons?

31. Which scientist proposed the term “Plum Pudding Model” to describe the structure of the atom?

32. Which of the following cannot be changed without changing to a new element.
Number of Electrons
Number of Neutrons
Number of Protons

33. What ancient Greek proposed an Atomic Theory that stated that all matter is composed of small, indivisible, indestructible particles?

34. Which scientist proposed “The nucleus of an atom is made up of particles called protons.”

35. The Atomic number of Titanium (Ti), when added to the Atomic Mass of Oxygen (O) equals the number of electrons of what element?

36. To calculate the weighted average atomic mass for an element you must know the mass of the different isotopes and their ______.

37. Isotopes of the same element will always have the same number of _________.