I. Atom and Ion theory questions
Atom questions
There are a total of 17 ion theory and atom questions, which are important content-oriented in the summary part of this chapter. Click the ‘Answer’ button to see the corresponding answers and explanations, and click the ‘Go back’ button to slove the next questions.
1. Which of the following is an INCORRECT pair for the history of atomic theory?
A. Dalton: the atom is the smallest particle and is spherical in shape.
B. Thomson: discovery of electrons by the cathode-ray tubes.
C. Millikan: discovery of nucleus by the scattering alpha (α) particles.
D. Rutherford: electrons revolve around the nucleus like planets around the sun.
E. Bohr: circling electrons around a nucleus with fixed paths.
2. Which of the following is an INCORRECT statement about atomic structure?
A. Atoms are composed of protons, neutrons, and electrons.
B. Nucleus is composed of neutrons and protons.
C. Atomic mass is increased with increasing number of neutrons.
D. Ionic atoms are formed by transferring protons or electrons from other atoms.
E. An element is distinguished by the number of protons.
3. Which of the following does NOT apply to atomic structure?
A. Nucleus which is composed of proton and neutron is positive.
B. Isoelectronics have the same number of electrons but different number of neutrons.
C. Isotopes have similar chemical characteristics but different physical characteristics.
D. Neutral atoms have the same number of protons and electrons.
E. Number of protons, or atomic number, is used for classification of atoms.
5. Which of the following phrases does NOT apply to isotopes?
A. Same number of protons
B. Different number of neutrons
C. Different number of mass
D. Same atomic numbers
E. All of the above
12. Four of the following atoms have the same number of electrons. Which one is different from the others?
A. A sulfur atom with two electrons added.
B. A chlorine atom with one electron added
C. Argon
D. A scandium atom with one electron removed.
E. A calcium atom with two electrons removed.
15. Tungsten- 184 is decayed by the emission of one alpha, two beta, and three gamma particles from an unknown nucleus. What is the unknown nucleus?
A. Rhenium-188
B. Rhenium-180
C. Tantalum-188
D. Tantalum-180
E. Tungsten-188
16. A daughter nucleus, hafnium, is formed from a parent nucleus, osmium. When 2 beta particles are emitted, then how many alpha particle(s) is(are) emitted?
A. 1
B. 2
C. 3
D. 4
E. 5
Answers
1. C
Millikan measured the mass of electron by oil-drop experiment. Discovery of nucleus by the scattering alpha (α) particles is Rutherford.
5. E
Isotopes have the same number of protons, but these have the different number of mass (neutrons).
6. ENeutral atoms have the same numbers of protons and electrons. These two atoms have different atomic mass (88 and 90) and different numbers of neutrons.
7. B
 |  | |
Protons | 4 = (atomic number) | 4 = (atomic number) |
Electrons | 4 = (atomic or proton number) | 2 = (atomic number – cations) = 4 - 2 |
Neutrons | 5 = (atomic mass – atomic number) | 5 = (atomic mass – atomic number) |
Atomic mass | 9 | 9 |
