Get premium membership and access revision papers, questions with answers as well as video lessons.

Chemistry Of The S And P Block Elements Question Paper

Chemistry Of The S And P Block Elements

Course:Bachelor Of Education Science

Institution: Kabarak University question papers

Exam Year:2009

KABARAK UNIVERSITY
UNIVERSITY EXAMINATIONS
2009/2010 ACADEMIC YEAR
FOR THE DEGREE OF BACHELOR OF SCIENCE IN
EDUCATION SCIENCE
COURSE CODE: CHEM 221
COURSE TITLE: CHEMISTRY OF THE S AND P BLOCK
ELEMENTS
STREAM: Y2S2
DAY: THURSDAY
TIME: 2.00 – 4.00 P.M
DATE: 10/12/2009

INSTRUCTIONS:
Attempt All Questions

QUESTION ONE (17.5 Marks)

a. Define the following terms
i. Electron affinity
ii. Electronegativity
iii. Electron shielding (6marks)
b. Give the electronic configurations of the following elements; Na-11, Mg-12, Li-3,Ce-
55 (3.5marks)
c. Explain the following observations
i. The M+
ion becomes more reactive down the group.
ii. In a flame test barium shows an apple green colour, calcium - brick red, strontium –
crimson red and radium - crimson red. (5marks)
d. Explain the diagonal relationship between Be and Al. (3marks)

QUESTION TWO (17.5 Marks)
a. The atomic radius of Al is expected to be less than that of Ga. However, the observed
atomic radius of Al (143 pm) is slightly more than that of Ga (l35 pm). Explain this
observation. (4marks).
b. The electronegativities of group 13 elements do not decrease smoothly: B 2.04; Al
1.61; Ga 1.81; In 1.78 and Tl 2.04. Explain the anomalous position of Gallium.
(3.5marks).
c. What are Boranes? Describe using equations any two methods of how you would
prepare Boranes. (6marks).
d. Ammonia has a higher boiling point than phosphine and then the boiling point increases down
the group as shown in the table below. Explain the abnormally high boiling point of
ammonia.
(4marks)

QUESTION THREE (17.5 Marks)
a. Define the following terms:
i. Catenation
ii. Allotropes (4marks)
b. There are three allotropes of sulphur name them. (3marks)
c. Explain the following observations
i. Oxygen unexpectedly has low electron affinity.
ii. Oxygen has unexpectedly low ionization energy than nitrogen. (6marks)

d. The volatility of the hydrides of group 6 elements increases from H2O to H2S and then
decreases as shown by their boiling points in the table below. Explain why the boiling
point of water is unexpectedly higher.
(4.5marks)

QUESTION FOUR (17.5Marks)

a. State and explain any three factors that would affect the magnitude of ionization energy
of any atom. (6marks)
b. Explain why all the halogens are coloured. (4marks)
c. Show the hybridization in IF7. Hence deduce the structure of this compound.
(4.5marks)
d. Enumerate any three uses of the noble gases. (3marks)

Chemistry Of The S And P Block Elements Question Paper

More Question Papers

Popular Exams