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Topic: structure periodicity and chemical bonding: check my answers???!!!  (Read 12205 times)

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Offline psychfan29

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1. The general electron configuration for atoms of the halogen group is:
                      my answer: ns^2np^7
2.  Consider the element with the electron configuration [Kr]5s^24d^7.  This element is:
                      my answer:  a transition metal
3.  True/False:  Cl- and S are isoelectronic:
                      my answer:  true
4.  Arrange the following ions in order of increasing ionic radius: Kk+, P3-, S2-, Cl-
                      my answer:  K+, Cl-, S2-, P3-
5.  For which of the following reactions is the enthalpy change equal to the second ionization energy of nitrogen?
                      my answer: N2+(G)---->N3+(g) + e-
6.  Which element will display an unusually large jump in ionization energy values between l3 and l4, its third and fourth ionization energies (Na, Mg, Al, Si, or P)?
                      my answer:  Mg
7.  For phosphorus atoms, which ionization energy will show an exceptionally large increase over the previous ionization energy (2nd, 3rd, 4th, 5th, or 6th)
                      my answer: 3rd
8. The successive ionization energies of a certain element are l1=589.5 kj/mol, l2=1145 kj/mol, l3=4900kj/mol, l4=6500kj/mol, and l5=8100 kj/mol.  This pattern of ionization energies suggests that the unknown element is (K, Si, As, Ca, or S):
                      my answer: Si
9.  Which of the following elements has the greatest electron affinity (K,Br, As, Ar or I):
                      my answer: K
10. Which of the following is a basic oxide (CO2, MgO, As2O3, SO2, or Cl2O7):
                      my answer: MgO
11.  Complete this statement: Coulomb's law states that the magnitude of the force of interaction between 2 charged bodies is________________________
                       my answer: directly proportional to the product of the charges on                               
                                       the bodies and inversely proportional to the square of 
                                       the distance separating them
12. The Lewis dot symbol for the calcium ion is:
                       my answer:    :Ca:2+
13.  Which one of the following ionic solids would have the largest lattice energy (NaCl, NaF, CaBr2, CsI, CaCl2):
                       my answer:  CaBr2
14.  Which of the following solids would have the highest melting point (NaF, NaCl, NaBr, NaI):
                       my answer:  NaI
15. Which of the following solids would have the lowest melting point (KI, KBr, KCl, KF):
                       my answer:  KCl
16.  Which of these elements has the greatest electronegativity (Na, As, Ga, Cs, Sb):
                       my answer:  As
17.  A polar covalent bond would form in which one of the following pairs of atoms (Cl-Cl, Si-Si, Ca-Cl, Cr-Br, P-Cl)
                       my answer: Cl-Cl
18. What type of chemical bond holds the atoms together withing a water molecule:
                       my answer: polar covalent bond
19. Which of these bonds would have the greatest polarity (Si-P, Si-S, Si-Se, Si-Cl, Si-I):
                       my answer:  Si-Cl
20. A nonpolar covalent bond would form in chich one of the following pairs of atoms (Na-Cl, H-Cl, Li-Br, Se-Br, Br-Br)
                       my answer: Na-Cl
21. The bond in which of the following pairs of atoms would be the least polar (C-Cl, C-C, C-H, O-C, N-C):
                       my answer:  N-C
22.  True/False: The electron dot formula for O2 shows:
                       my answer:  a double bond
23.  The total number of lone pairs in NCl3 is:
                       my answer: 10
24.  The number of resonance structures for the sulfur dioxide molecule that satify the octet rule is:
                       my answer: 1
25. How many resonance structures are there for the cyclobutene molecule (C4H6; the four carbon atoms are arranged in a ring):
                       my answer: 2
26.  What is the formal charge on the oxygen atom N2O (the atomic order is N-N-O):
                       my answer: -2
27.  According to the VSEPR theory, the geometry of the SO3 molecule is:
                       my answer: trigonal planar
28. The geometry of the ClF3 molecule is best described as:
                       my answer: T-Shaped
29.  According to the VSEPR theory, which one of the following would be linear (H2S, HCN, BF3, H2CO, SO2):
                       my answer:  HCN
30.  The bond angle in Cl2O is expected to be approximately:
                       my answer: 120
31.  The F-S-F angles in SF6 are:
                       my answer: 109.5
32. According to the VSEPR theory, the ACTUAL F-AS-F bond angles in the AsF4- ion are predicted to be:
                       my answer: 109.5
33.  Which one of the following molecules has a zero dipole moment:
                       my answer:  CH2Cl2
34. What is the hybridization of the As atom in the AsF5 molecule:
                       my answer: sp3d2
35.  Which of the following have the same geometries (NH2- and H20, NH2- and BeH2, H2O and BeH2, NH2-, H2O, and BeH2):
                       my answer:  H2) and BeH2
36.  The number of pi bonds in the oxalate ion (C2O42-) is:
                       my answer:  2
37.  Consider the species Cl2+, Cl2, and Cl2-. Which of ehse species will be paramagnetic:
                       my answer:  Only Cl2
38. Consider the species N2-, N2, and N2+.  Which of these will be paramagnetic;
                       my answer:  N2+ ad N2-
39.  In which of the following would the bonding be weakened with the addition of an electron to form the negative molecular ion (B2, C2, N2, all of these, or none of these):
                       my answer:  C2
40.  Which of the following molecules is nonpolar (NH3, OF2, CH2Cl, H2O, or BeCl2):
                       my answer:  NH3

« Last Edit: December 17, 2007, 09:14:39 PM by psychfan29 »

Offline enahs

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Re: structure periodicity and chemical bonding: check my answers???!!!
« Reply #1 on: December 17, 2007, 07:09:50 PM »
I do not feel like going through them all, so I will tackle the first 4 (10%); and let somebody else tackle some more.
1) I am a tard who does not know how to read or write, see Sev's post. heh
2) A transition metal? Which one?
3) The electron has a negative charge, so a molecule with an extra negative charge has extra electrons, not less. A positive charge indicates there are more protons then electrons, and thus has lost an electron. With that said, is Cl- isoelectronic with S (count the number of electrons).
4) Looks good to me.




« Last Edit: December 17, 2007, 07:51:36 PM by enahs »

Offline Sev

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Re: structure periodicity and chemical bonding: check my answers???!!!
« Reply #2 on: December 17, 2007, 07:50:22 PM »
1. ignoring other subshells, ns2np5

Offline Yggdrasil

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Re: structure periodicity and chemical bonding: check my answers???!!!
« Reply #3 on: December 17, 2007, 08:02:43 PM »
5 is incorrect.  For answering this question, it's helpful to first think of the equation for the first ionization energy and then the second ionization energy:

1st ionization:  N --> N+ + e-
2nd ionization: N+ --> N2+ + e-
3rd ionization: N2+ --> N3+ + e-
etc.

This likely has an effect on some of the answers directly after it.

Offline Padfoot

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Re: structure periodicity and chemical bonding: check my answers???!!!
« Reply #4 on: December 17, 2007, 08:47:05 PM »
Check the Ionisation energy questions like Yggdrasil said
9) You forgot to post the choices
10) Correct
11) Correct again

Offline psychfan29

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Re: structure periodicity and chemical bonding: check my answers???!!!
« Reply #5 on: December 17, 2007, 09:16:03 PM »
Check the Ionisation energy questions like Yggdrasil said
9) You forgot to post the choices
10) Correct
11) Correct again
Oh...yea...lol okay I added the choices now...sorry about that... :-[

Offline LQ43

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Re: structure periodicity and chemical bonding: check my answers???!!!
« Reply #6 on: December 19, 2007, 12:30:38 AM »
I'll do some from the bottom

30. incorrect, its bent with 2 Lone Pairs
31. incorrect, its octahedral
32. correct
33. incorrect - you forgot to give the other choices
34. incorrect, 5 pairs of electrons, what is hybridization
35. incorrect, draw Lewis structure of NH2-
36. correct
37. incorrect (see your answer to 38)
38. correct
39. incorrect, bonding is weakened when the electron goes into an antibonding MO
40. incorrect (polar - central atom has Lone pairs OR outside atoms are not the same)

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