Name: ________________________ Class: ___________________ Date: __________ ID: A

4

2009-2010 SCH4C Unit 1 Test 2

Modified True/FalseIndicate 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 ChoiceIdentify 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 isA) a nonelectrolyte C) a conductorB) an electrolyte D) an insulator

____ 17. Sodium chloride is an example ofA) an ionic compound C) a saltB) an electrolyte D) all of the above

____ 18. If an atom gains two extra electrons, it has a charge ofA) 2+ C) 1−B) 2− D) none of the above

____ 19. The octet rule states thatA) atoms must gain or lose 8 valence electrons to be stableB) atoms must lose 8 valence electrons to be stableC) atoms can only be stable when they gain 8 valence electronsD) atoms are stable when they have 8 valence electrons

____ 20. When an atom gains one or more electrons, the number of protonsA) decreases C) stays the sameB) increases D) none of the above

Name: ________________________ ID: A

2

____ 21. In order to become like a noble gas, metals usually tend to A) gain electronsB) lose electronsC) gain or lose electrons depending on the metalD) none of the above

____ 22. An ion with a +3 charge hasA) three extra electrons C) one missing proton, two extra electronsB) three missing 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 atomsB) the metal atoms lose electrons to other metal atomsC) the nonmetal atoms lose electrons to the metal atomsD) the nonmetal atoms lose electrons to other nonmetal atoms

____ 24. A single covalent bond is formed whenA) two atoms share two electronsB) two atoms both lose electronsC) one atom gains electrons from the other atomD) the electrons are passed back and forth between the two atoms

____ 25. Covalent compounds formA) molecules C) polyatomic ionsB) crystals D) none of the above

____ 26. Four electrons shared between two atoms is known asA) a quadruple bond C) a double bondB) a triple bond D) none of the above

____ 27. Valence electron pairs that are not involved in bonding are calledA) non-bonding electrons C) spectator electronsB) a lone pair of electrons D) nothing; they do not have a name

____ 28. In a Lewis structure, lone pairs of electrons are drawnA) to show that each atom has a complete octetB) to make the diagram simpler to drawC) to make the diagram harder to drawD) 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 itsA) ionization energy C) electronegativityB) 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 ChorlineTO 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

Name: ________________________ ID: A

3

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 indicateA) 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 dioxideb) trioxideTO BE ADDED

37. For the following diagram answer the following quesitons.a) What element is represented in the Bhor-Rutherford diagram. (1Tmark)sodiumb) What is missing at A and B. (2T mark)c) At location C drow the resulting ion as a Bohr Rutherford diagram. (4C marks)

Name: ________________________ ID: A

4

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)