Name: Class: Date: Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

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1 Name: Class: Date: SCH4U Chapter 3 Test Retest Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Which situation must be true for two electrons to occupy the same orbital? A) The electrons must have the same spin. B) The electrons must have identical sets of quantum numbers. C) The electrons must have low energy. D) The electrons must have the opposite spin. E) none of the above 2. How many d sub orbitals are in each energy level, except n = 1? A) 1 B) 3 C) 5 D) 6 E) 7 3. Which statement about the principle quantum number is INCORRECT. A) The principal quantum number, indicates the energy level of an atomic orbital and its relative size. B) it is a positive or negative whole number starting at 1 C) is designated by the symbol n D) a higher value of n indicates a higher enrgy level E) a higher value of n a higher probability of finding electrons farther from the nucleus 4. The following diagram represents which d orbital? A) x 2 -y 2 B) xz C) yz D) z 2 E) x-y 5. The greatest number of electrons that is possible for any energy level is found using the following fromula A) 2n 2 B) 2n C) n 2 D) 2n 3 E) 2+n 2 6. The 4f orbitals do not start to fill until the following orbital is already filled A) 6s B) 4s C) 6p D) 7s E) 1s 7. Which of the following statements about ionic bonding is INCORRECT. A) The force of attraction between oppositely charged ions (cations and anions) consitutes an ionic bond. B) Ionic bonding occurs between atoms of elements that have large differences in electronegativity. C) The units of ionic compounds can be seperated easily by direct heating of the crystal salt. D) The ions that make up the ionic solid are arranged in a specific array of repeating units. E) The ions that make up the ionic solid are arranged in a rigid lattice structure so that the cations and anions are arranged so that the system has the minimum possible energy. 8. Which one of the following statements about covalent bonding is CORRECT. A) Covalent bonding involves an inbalance between the forces of attraction and replusion that act between the nuclei and electrons of two or more atoms. B) There is an optimum seperation between the individual atoms involved in a covalent bond at which the nucleus-electron attactions, nucleus-nucleus replusions, and electron-electron repulsions acheive a balance. C) Lithium Sulfide is an example of a molecule with covalent bonds. D) A covalent bond involves the formation a new orbital, caused by the overlapping of atomic orbitals. The new orbital has energy levels that are higher than those of the original atomic orbitals. E) In many cases, electron sharing enables each atom in a covalent bond to acquire full d orbital. 1

2 Name: 9. In the liquid state, polar molecules (dipoles) orient themselves so that oppositely charged end of the molecules are near to the one another. The attraction between these opposite charges are called A) dipole-dipole forces D) dipole induced forces B) ion dipole forces E) intramolecular forces C) ion induced dipole forces 10. Non-polar gases such as oxygen and nitrogen dissolve sparringly, in water because of these forces. A) dipole - dipole forces B) ion dipole forces C) ion induced dipole forces D) dipole induced dipole forces E) london dispersion forces 11. Which of the following is NOT an intermolecular bond. A) ionic C) hydrogen D) dispersion E) dipole-dipole B) ion-dipole 12. Which of the following statements is CORRECT for two bonded atoms that have very different electronegativities. A) The atom with the lower electronegativity attracts the shared electrons more strongly than the atom with the higher electronegativity. B) The atom with the higher electronegativity attracts the shared electrons more strongly than the atom with the lower electronegativity. C) If the EN is greater than 0.4 and less than 1.7 the bond is considered ionic. D) both A and C are correct E) both B and C are correct 13. The factor(s) that effect the magnitude of dispersion forces. A) number of electrons D) Both A and B B) the shape of the molecule E) Both A and C C) the electron group arrangement 14. A molecule with the VSEPR notation of AX 2 E. A) will never be polar B) will always be polar C) will only be polar if the bond dipoles are in the direction of the central atom D) will only be polar is the bond dipoles are in the direction of the peripheral atoms E) will only be polar if the bond dipoles are in opposite directions 15. The reason the atoms form chemical bonds is that A) bonded atoms tend to have lower energy than single, uncombined atom B) bonded atoms tend to have higher energy than single, uncombined atom C) bonded atoms need to obtain an octect valence shell of electrons D) bonded atoms need to lose or gain electrons E) bonded atoms tend to have stable ions Short Answer Each question is out of 5 level marks. Grading will be based upon the quality of your answer and how clearly you present the information within your answers. You are expected to incorporate key terms and concepts you have learned. An overall communcation mark will be given for all answers. 16. Explain in detail (name, symbol, qualities, discriptors etc.) the fourth quantum number and explain in what way it if different from the other three quantum numbers in terms of how it is determined/calculated? (K) The forth quantum number is called the spin quantum number (ms) specifies the direction in which the electron is spinning on an axis given the values +1/2 or -1/2 clock or counter respectively. It is different from the other three QMs on how it is determined b/c it is determined using emperical evidence (observation of it s paticle like nature) not on wave equations 2

3 Name: 17. Write the expected and actual condensed electron configuration for Cr and explain why the actual configuration exists. (K) Expected [Ar] 4s 2 3d 4 Actual [Ar] 4s 1 3d 5 Using the rules/principles of QM (aufbau principle and Hund s rule) in most cases result in the most stable configuration for the atom. However in the case of Cu experimental evidence indicates atoms achieve a stable configuration that do not confirm or follow the rules above. For Cr a half filled 4s orbital and a 1/2 filled 3d orbital is more stable than the expected configuration. 18. Explain the factors the govern the change in atomic radius across a period. (assume only period 2 and 3) (for full marks you answer must include the concepts of Zeff, changing n and sheilding) (K) Zeff governs or controls the trend of decreasing atomic radius across a period. Across a period each atom has one more elctron added to it s valence level (same nrg level...or in the case of the inner transition in the lower level) n does not change. The shielding effect changes only slightly but Zeff changes considerably. The decrease in atomic radius therefore is controled by the increase in Zeff that occurs across a period. 19. Use VSEPR theory to draw the lewis structure for HCN. Show the math, don t forget to consider resonance structures and fill in the table below. (C) Num of electron groups Geometric Arrangement of electron groups Types of electron pairs VSEPR notation 2 linear 2 BP AX2 linear Name of Molecular Shape 3

4 Name: 20. Discuss the validity of the statement: All polar molecules must have polar bonds and all non-polar molecules must have non-polar bonds. (C) All polar molecules must have polar bonds, however not all non-polar molecules have non-polar bonds. (i.e. some non polar molecules can and do have polar bonds). If the bonds in the molecule are polar but the molecule is symetrical (for example in a trigonal planner or tetrahedral molecule) the dipoles of individual bonds cancel each other to give a net zero dipole the molecule will be non-polar. Ex CCl4 is non polar molecule with four polar bonds. 21. For each of the following elements or ions write the appropriate format indicated. (C) a) O - condensed electron configuration b) S - orbital diagram c) Br -1 - full electron configuraiton will be added first day back 22. Consider the following graph of ionization energy. Explain the drop in IE for Group 16 elements in Period 2 and 3. (T) The drop in B and Al occurs because electrons start to fill the np orbitals which are higher in energy than the ns orbitals so the additional e is more easily removed. Group 16 marks the first pairing of the p orbital electrons. THe np3 configuration of nitrogen is more stable than the np4 configurations of oxygen. E repulsions increase the orbital energy in O and S therefore less nrg is required to remove the 4th p sublevel e 23. How many filled or partially filled sub-orbitals does the Iodine atom have? (assume ground state and filled = max number of electrons in the suborbital) List using electron configuration notation the partially filled orbital(s). (T) 1s22s22p63s23p64s23d104p5 17 filled and 1 partially filled the 4pz 4

5 Name: 24. Explain what is wrong with each set of quantum numbers. (note there may be no errors) (T) same as practice n l ml ms / / / /2 25. Explain the following two diagrams. (i.e. what do they represent? What does it tell the person that is looking at it?) For full marks all parts of the diagram will need to be labled correctly. will be added first day back 5