Name: ________________________ Class: ___________________ Date: __________
ID: A
2009-2010 SCH4C Unit 1 Test 2
Modified True/False
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the
sentence or statement true.
____
1. F The ability of a substance to conduct electricity is called electrolysis. conductivity
____
2. F Atoms that have gained extra valence electrons are known as cations. anions
____
3. T Valence electrons are those electrons found in the outermost shell of an atom. _________________________
____
4. T A Lewis symbol is a diagram that shows the number of valence electrons for an atom.
_________________________
____
5. F Ions that are composed of more than one atom are called monatomic ions. polyatomic ions
____
6. F The force of attraction between two oppositely charged ions is called a covalent bond. ionic bond
____
7. T Within a polar covalent bond, the bonding electron pair is not shared equally. _________________________
____
8. T A flame test is a method for identifying different types of matter using qualitative analysis?
______________________
____
9. F A full outer shell usually means six valence electrons. eight
____ 10. F When using Lewis symbols, the number of dots represents the total number of electrons.
valance
____ 11. T Most molecules exist in 3D space, that is on an x, y and z axis.
_______
____ 12. T If only two atoms are bonded together with different lectronegativities than you will have a polar molecule.
_____________________
____ 13. T If sodium loses one electron, it now has eight valence electrons in it’s outer most shell.
_____________________
____ 14. F Ionic compounds form polyatomic ions.
crystals or formula units
____ 15. F The element with the highest electronegativity is francium.
flourine
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____ 16. A compound that is able to conduct a current when placed in water to form a solution is
A) a nonelectrolyte
C) a conductor
B) an electrolyte
D) an insulator
____ 17. Sodium chloride is an example of
A) an ionic compound
B) an electrolyte
C) a salt
D) all of the above
____ 18. If an atom gains two extra electrons, it has a charge of
A) 2+
C) 1−
B) 2−
D) none of the above
____ 19. The octet rule states that
A) atoms must gain or lose 8 valence electrons to be stable
B) atoms must lose 8 valence electrons to be stable
C) atoms can only be stable when they gain 8 valence electrons
D) atoms are stable when they have 8 valence electrons
____ 20. When an atom gains one or more electrons, the number of protons
A) decreases
C) stays the same
B) increases
D) none of the above
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Name: ________________________
ID: A
____ 21. In order to become like a noble gas, metals usually tend to
A) gain electrons
B) lose electrons
C) gain or lose electrons depending on the metal
D) none of the above
____ 22. An ion with a +3 charge has
A) three extra electrons
B) three missing electrons
C) one missing proton, two extra electrons
D) one extra proton, two missing electrons
____ 23. During the formation of an ionic bond,
A) the metal atoms lose electrons to the nonmetal atoms
B) the metal atoms lose electrons to other metal atoms
C) the nonmetal atoms lose electrons to the metal atoms
D) the nonmetal atoms lose electrons to other nonmetal atoms
____ 24. A single covalent bond is formed when
A) two atoms share two electrons
B) two atoms both lose electrons
C) one atom gains electrons from the other atom
D) the electrons are passed back and forth between the two atoms
____ 25. Covalent compounds form
A) molecules
B) crystals
C) polyatomic ions
D) none of the above
____ 26. Four electrons shared between two atoms is known as
A) a quadruple bond
C) a double bond
B) a triple bond
D) none of the above
____ 27. Valence electron pairs that are not involved in bonding are called
A) non-bonding electrons
C) spectator electrons
B) a lone pair of electrons
D) nothing; they do not have a name
____ 28. In a Lewis structure, lone pairs of electrons are drawn
A) to show that each atom has a complete octet
B) to make the diagram simpler to draw
C) to make the diagram harder to draw
D) only if you want to
____ 29. The measure of an atom’s ability to attract a pair of electrons it shares with another atom in a covalent bond is
known as its
A) ionization energy
C) electronegativity
B) electron affinity
D) electron attraction
____ 30. The following in a tetrahedral molecule model.
A)
C)
B) correct one
D)
Short Answer
31. Using Lewis Symbols and the octect rule, illustrate how each of the following paris of atoms form ionic bonds.
(4C marks each)
a) Potasium and Chorline
TO BE ADDED
32. Explain how and why an ion is formed. (4C marks)
An ion is formed when an atom gains or loses one or more electrons. Atoms form ions in order to become
more stable by attaining 8 (an octet of) valence electrons
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Name: ________________________
ID: A
33. Why does sodium have an octet of electrons when it loses its valence electron? Support your answer with a
diagram. (4C marks)
When sodium loses its one valence electron, its outermost shell is now empty. The second energy level (the
one underneath) is now full (i.e., it has 8 electrons).
34. How does a polar bond differ from a nonpolar bond? (4Cmarks)
- in a polar bond, the shared pair of electrons spends more time close to the atom with the higher
electronegativity, causing the molecule to form a dipole (one end is more negative and the other end is
more positive)
- in a nonpolar bond, the electrons spend equal time near each atom and thus, no dipole is created
35. List the information that is presented in the chemical formulas of an ionic compound.(4C marks)
Chemical formulas of ionic compounds indicate
A)
the type of atoms in the compound
B)
the ratio of the types of atoms in the compound
C)
a formula unit of the compound
36. Draw the Lewis structure for the following molecular compounds. (4C marks each)
a) silicon dioxide
b) trioxide
TO BE ADDED
37. For the following diagram answer the following quesitons.
a) What element is represented in the Bhor-Rutherford diagram. (1Tmark)
sodium
b) What is missing at A and B. (2T mark)
c) At location C drow the resulting ion as a Bohr Rutherford diagram. (4C marks)
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Name: ________________________
ID: A
38. For the following model of NH3 and CH3Cl answer the following questions.
Answer Q 6 and 8 on your foolscap.
1) Identify the central atom(s) with a C and the peripheral atom(s) with a P. (2T marks)
3) List total number of bonding pairs and lone pairs around the central atom. (4T marks)
a)# of bonding pairs _________ number of lone pairs _________
b)# of bonding pairs _________ number of lone pairs _________
4) What is the shape of the molecule? (2T marks)
a)Shape _____________________
b)Shape _____________________
6) Calculate the electronegativity difference between each pair of covalent bonds.(4T marks)
7) Draw dipole vectors for each polar bond on the model. (4T marks)
8) Is this a polar molecule. Explain. (4C marks each)
a)
b)
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