1. أسئلة مراجعه للباب الثاني Revision of Chapter 2
Atoms, Molecules & Ions
إعداد
د. هنادي يوسف مدراسي
أستاذ الكيمياء العضوية المساعد
مراجعة وتنقيح
أ. د. أميرة صالح العطاس
أستاذ الكيمياء التحليلية
قسم الكيمياء
جامعة الملك عبد العزيز-فرع الفيصلية

2. 1. Which of the following expressions represents two molecules of water?
2. Which molecule from the following has the largest mass
A HBr
B HCl
C HF
D HI *
3. Which of these compounds is a binary compound?
NaCl *
MgSO4
NaOH
HCN
4. Which of these compounds is a ternary compound?
NaCl
H2O
NaOH *
MgBr2
Chapter 2

3. 5. A compound has the empirical formula HC and molecular mass 78.11 g.
The molecular formula could be written as:
H2C2
H4C4
H5C5
H6C6 *
6. The formula of stannic oxide is SnO2. The valence of Sn is: A B C
D *
7. Atoms with the same number of electrons and number of protons are called…
ions
isotopes
neutral atoms *
different atoms
8. Al 3+ is an example of one of the following:
A. amonatomic anion
B. monatomic cation *
C. a polyatomic cation
D. a polyatomic anion
Chapter 2

4. Chapter 2 9. Which of the following molecule is a diatomic molecule ?
N2O
N2O4
NO2
NO *
10. One of the following molecule is not a polyatomic molecule:
A NH3
B CH4
C H2O
D HCl *
11. Atoms which have different number of electrons are called…
ions *
isotopes
neutral atoms
different atoms
12. SO42+ is an example of one of the following:
A. amonatomic anion
B. monatomic cation
C. a polyatomic cation
D. a polyatomic anion*
Chapter 2

5. 13. Which of the following expressions represents three moles of amonia?
NH3
NH4+
3 NH3 *
N3H6
14. The Stock system name for FCl3
A. Iron (II) chloride
Iron (III) trichloride
Iron (III) chloride *
D. monoiron trichloride
15. Which of these ions is a monoatomic ions ?
Na+ *
SO42-
NO3-
NH4+
16. Which of these compounds is a ternary compound?
NaCl
H2O
NaOH *
MgBr2
Chapter 2

6. 17. Which of the following expressions represents two molecules of water?
18. A compound has the empirical formula HC and molecular mass g. The molecular formula could be written as:
H2C2
H4C4
H5C5
H6C6 *
19. Which of these compounds is a binary compound?
NaCl *
MgSO4
NaOH
HCN
20. Which of these compounds is a ternary compound?
NaCl
H2O
NaOH *
MgBr2
Chapter 2

7. Chapter 2 21. An anion is defined as
A. a charged atom or group of atoms with a net negative charge. *
B. a stable atom.
C. a group of stable atoms.
D. an atom or group of atoms with a net positive charge.
22. An cation is defined as … 
A. a charged atom or group of atoms with a net negative charge.
B. a stable atom.
C. a group of stable atoms.
D. an atom or group of atoms with a net positive charge. *
23. Atoms of the same element with different mass numbers (or number of neutrones)
are called … 
A. ions.
B. neutrons.
C. allotropes.
D. chemical families.
E. isotopes *
24. How many neutrons are there in an atom of lead 82Pb whose mass number is 208? 
A. 82
B. 126 *
C. 208
D. 290
Chapter 2

8. 25. molecules consist of the same element with different numbers of atoms and chemical structure are called … 
A. ions.
B. neutrons.
allotropes *
isotopes.
26. A magnesium ion, 12Mg2+, has 
A. 12 protons and 13 electrons.
B. 24 protons and 26 electrons.
C. 12 protons and 10 electrons. *
D. 24 protons and 22 electrons.
E. 12 protons and 14 electrons.
27. A sulfide ion, 16S2- , has: 
A. 16 protons and 16 electrons
B. 32 protons and 16 electrons
C. 16 protons and 14 electrons
D. 16 protons and 18 electrons *
E. 32 protons and 18 electrons
Chapter 2

9. 28. Which of these elements is most likely to be a good conductor of electricity? 
A. N
B. S
C. He
D. Cl
E. Fe *
29. Which of these pairs of elements would be most likely to form an ionic compound? 
A. P and Br
B. Cu and K
C. C and O
D. O and Zn *
E. Al and Rb
30. Which of these pairs of elements would be most likely to form a molecular compound? 
A. Na and Br
B. Ca and O
C. C and O *
D. Zn and O
E. Mg and Cl
31. What is the formula for the ionic compound formed by calcium ions and nitrate ions? 
A. Ca3N2
B. Ca(NO3)2 *
C. Ca2NO3
D. Ca2NO2
E. CaNO3
Chapter 2

10. Chapter 2 32. Which is the correct formula for copper(II) phosphate?
A. Cu2PO4
B. Cu3(PO4)2 *
C. Cu2PO3
D. Cu(PO4)2
E. Cu(PO3)2
33. The correct name for NH4NO3 is 
A. ammonium nitrate. *
B. ammonium nitrogen trioxide.
C. ammonia nitrogen oxide.
D. hydrogen nitrogen oxide.
E. hydrogen nitrate.
34. The correct name for PCl5 is 
A. monophosphate pentachloride
B. phosphorus chloride
C. chlorophosphate
D monophosphate tetrachloride
E. phosphorus pentachloride *
Chapter 2

11. 35. Use the following table and choose which of the species are neutral?
Atom or ion element I II
III IV V VI
Atom or ion electrons (e) 6 10 18 28 7
Atom or ion protons (p) 8 17 11 30
Atom or ion neutrons (n) 36
III and V C. II and III
IV and V D. I and VI *
36. Use the following table and choose which of the species are negatively charged?
Atom or ion element I II
III IV V VI
Atom or ion electrons (e) 6 10 18 28 7
Atom or ion protons (p) 8 17 11 30
Atom or ion neutrons (n) 36
III and V C. II and III *
IV and V D. I and VI
Chapter 2

12. 37. Use the following table and choose which of the species are positively charged?
Atom or ion element I II
III IV V VI
Atom or ion electrons (e) 6 10 18 28 7
Atom or ion protons (p) 8 17 11 30
Atom or ion neutrons (n) 36
III and V C. II and III
IV and V * D. I and VI
38. An atom of the isotope 16S-31 consists of how many protons, neutrons,
and electrons? (p = proton, n = neutron, e = electron) 
A. 15 p, 16 n, 15 e
B. 16 p, 15 n, 16 e *
C. 16 p, 31 n, 16 e
D. 32 p, 31 n, 32 e
E. 16 p, 16 n, 15 e
Chapter 2

13. Chapter 2 39. Which is the formula for the dinitrogen pentoxide A. NO2
A. NO2
B. N2O5 *
C. N2O7
D. N2O2
40. The name for the group of those elements (F, Cl, Br, I) is:
A. Halogen group *
B. Nobel gase
C. Alkaline group
D. Transition metal group
41. Chromium (24Cr ) element is : 
A. A metal
B. found in groups B
C. found in period 4
D all the above *
Chapter 2