Atomic And Molecular Structure
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- 1.
- A.
Protons are found in the nucleus and are positively charged particles
- B.
Electrons move around the nucleus and contribute little to the mass of the atom
- C.
Neutrons are found in the nucleus and they have no charge
- D.
The numbers of neutrons, protons and electrons are always equal in a neutral atom
- 2.Mass number refers to:
- A.
The number of protons in the nucleus of an atom.
- B.
The number of electrons in an atom.
- C.
The number of neutrons in an atom.
- D.
The total number of protons and neutrons in the nucleus of an atom.
- 3.Atoms of the same element which have the same number of protons but a different number of neutrons are known as
- A.
Ions.
- B.
Isotopes.
- C.
Neutral atoms.
- D.
A chemical family.
- 4.Which of the following determines the size of an atom?
- A.
The number of protons in the atom.
- B.
The number of neutrons in the atom.
- C.
The size of the nucleus of the atom.
- D.
The number of electrons in the atom.
- 5.The electron configuration: 2, 8, 4 is that of:
- A.
Carbon
- B.
Nitrogen
- C.
Neon
- D.
Silicon
- 6.The electron configuration for Al3+ is
- A.
2, 8, 3
- B.
2, 8
- C.
2, 8, 6
- D.
2, 8, 2
- 7.Which of the following is the most important factor in determining the chemical properties of an element?
- A.
The total number of electrons in its atoms.
- B.
The number of protons in the nucleus of its atoms.
- C.
The number of neutrons in the nucleus of its atoms.
- D.
The number of valence electrons in its atoms.
- 8.The number of valence electrons in an atom is equal to
- A.
The number of electrons in the atom.
- B.
The charge on a positive or negative ion formed by that atom.
- C.
The number of electrons in the outer energy level of the atom.
- D.
The number of electrons needed to fill all the energy levels of the atom.
- 9.An element, X, has the following electron configuration: 2, 5The atomic number of element X would be:
- A.
2
- B.
5
- C.
7
- D.
3
- 10.An element, X, has the following electron configuration: 2, 5The number of valence electrons in element X is
- A.
2
- B.
5
- C.
7
- D.
3
- 11.The number of valence electrons in the Group 2 elements of the Periodic Table is
- A.
2
- B.
4
- C.
6
- D.
8
- 12.Which of the following species does NOT have a stable electron configuration (i.e. like those of an inert gas)?
- A.
Cl-
- B.
K+
- C.
Al3+
- D.
Mg+
- 13.If an element has the electron configuration: 2, 8, 2 then it would most likely form an ion of charge
- A.
+2
- B.
-2
- C.
+6
- D.
-6
- 14.Which one of the following statements about atomic structure is TRUE?
- A.
The numbers of protons, neutrons and electrons is always equal in a neutral atom.
- B.
The numbers of protons and neutrons are always equal in a neutral atom.
- C.
The numbers of neutrons and electrons are always equal in a neutral atom.
- D.
The numbers of protons and electrons are always equal in a neutral atom.
- 15.Electrons are thought to be located in distinct energy levels or shells in an atom. The maximum number of electrons which can be found in the third (n=3) shell of an atom is:
- A.
2
- B.
8
- C.
18
- D.
36
- 16.Which one of the following is the most important factor that determines the chemical properties of an element?
- A.
The number of protons in the nucleus of the atom.
- B.
The total number of electrons in the atom.
- C.
The number of valence electrons in the atom.
- D.
The number of neutrons in the nucleus of the atom.
- 17.
- A.
AB
- B.
A2B
- C.
AB2
- D.
A3B
- 18.Consider three elements A ,B and C which have atomic numbers less than 20. The atomic number of A and B are x and (x-3) respectively. Element A forms cations with formula A+ and forms a solid substance AC when it reacts with element C.Which one of the following elements could be A?
- A.
Li
- B.
Na
- C.
Cl
- D.
O
- 19.Consider three elements A ,B and C which have atomic numbers less than 20. The atomic number of A and B are x and (x-3) respectively. Element A forms cations with formula A+ and forms a solid substance AC when it reacts with element C.Which one of the following elements could be B?
- A.
Li
- B.
Na
- C.
Cl
- D.
O
- 20.Consider three elements A ,B and C which have atomic numbers less than 20. The atomic number of A and B are x and (x-3) respectively. Element A forms cations with formula A+ and forms a solid substance AC when it reacts with element C.The most likely type of bond formed between A and B would be:
- A.
Metallic bonds
- B.
Covalent bonds.
- C.
Ionic bonds.
- D.
Hydrogen bonds.
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