Practice for “Midterm 7”
Chem 1000 2004
Your responsible for the following sections of the text:
Chapters 16.4-16.5; 17.1-17.5; 18.1.
Representative questions: 16. 32, 35-38, 41-46, 62. 17.1, 3, 5, 9, 11, 14, 15, 19, 25, 27, 28, 29, 35, 36, 41, 47.
18.3-18.
Question One (5 marks)
On the above periodic table:
(a) Indicate the s, p, d and f blocks.
(b) Indicate the general trend of first ionization energy across the rows and down the groups.
(c) Indicate the general trend of the atomic radii across the rows and down the groups.
(d) Indicate the general trend of electronegativity across the rows and down the groups.
Question Two (6 marks)
The following may have more than one correct answer. Note, the atomic number is given in parentheses.
(a) Which of the following species has the largest ground state radius?
Br (35), Ca2+ (20), H (1), Br- (35), Fe3+ (26)
(b) Which of the following elements is the most electronegative?
Cl (17), Cs (55), W (74), Mg (12), Si (14)
(c) Which of the following species has the highest ionization energy?
Mg (12), Co (27), P (15), Mg2+ (12), Fr (87)
(d) Which of the following ions have d subshell valence electrons?
Cl - (17), Na+ (11), Fe2+ (26), U+ (92), Ag+ (47)
Question Four (three marks)
i) Which of the following elements has the greatest electronegativity: He, K, Co, S or Cl? Explain your
reasoning.
Question Four (three marks)
Give electron configurations for the following AND indicate whether they are diamagnetic or paramagnetic.
Si
As3+
Y
Question Five (five marks)
i)
Of silane (SiH4) and methane (CH4), which is the bigger molecule? Explain.
ii)
Of CI4 and KI, which has the higher boiling point? Explain.
iii)
Of Rb and K, which has the higher first ionization energy? Explain.
iv)
Of P and Cl, which has the greater electron affinity? Explain.
v)
Of the C—Cl and C—Br bond, which is the strongest? Explain.
Question Six (three marks)
Complete the following table with respect to the C—N bonds of the three compounds shown.
Bond Order
H3C
NH2
H2C
NH
H
C
Bond strength
(kJ/mol)
615
N
Bond length (Å)
1.29
1.15
Question Eight
What is the Pauli exclusion principal?
Question Six (4marks)
i) Give electron configurations for the following:
Cu
Sn2+
Clii)
Which of the species above is/are paramagnetic?
Question Ÿ
You live in the Zborkian Universe which has a different set of fundamental physical laws. The rules for
quantum nos. are the same as our own with the exception that m l can have any value 0, 1, ... l (letter ell). Sketch
the Zborkian Periodic Table up to the end of the 5th shell.
Question Three (2 marks)
Of the following bonds, C—Cl and C—Br, which is shorter? Explain your reasoning.
Question Four (3 marks)
Of PCl5 and MgI2 , which is more likely to be an ionic compound? Explain your reasoning.