1. (a) Define the following terms:-
i.Atoms
ii.Atomic number
iii.Mass number
iv.Electron
(b) State Dalton’s atomic theory
2. (a) Draw a simple diagram showing Electrons , Nucleus&
protons.
(b) Show the properties of subatomic particles in for of their charge
and mass.
3. Element X has an atomic number of 20.
State the group and period to which it belongs.
5.The following table shows the
atomic radii of elements A, B and C (
not the actual symbols of the elements) . Use it to answer the question that
follow
|
Element |
Atomic
radii (nm) |
Ionic
radii(nm) |
|
A |
0.113 |
0.096 |
|
B |
0.085 |
0.109 |
|
C |
0.172 |
0.171 |
a).Explain why the atomic radius of
element A is larger than its ionic
radius?
b). Explain why element A has a
very high melting point
c).Which element is the strongest
oxidizing agent
d).Element A and C react to form a while compound . In what
state does the compound conduct electricity current? Explain
6.Element P and Q ( not actual symbols)
have atomic numbers 8 and 11 respectively write down the symbol of their ions.
7.Argon can be represented as 40 AR
white down the number of protons ,
electrons and neutrons present in an atom of argon.
8. The table below show atomic radii of
elements in period 3 of the periodic table
|
Element |
Na |
Mg |
Al |
Sil |
P |
S |
Cl |
|
Atomic radius (nm) |
1.90 |
1.60 |
1.43 |
1.32 |
1.28 |
1.27 |
o.99 |
Explain
the trend in the atomic radii across the period.
9.Sodium burns in oxygen to form white
fumes. Write down the equation for the reaction.
10. Element P and Q (not actual symbols)
are alkali metals. Element P is higher than Qin the periodic table.
a)Which of the
two elements is more reactive ? Explain
b).Compare the ionization energies of element P and Q.
c).Write down the formula of their
chlorides.
11. The atomic number of calcium,oxygen
and chlorine atoms are 20 ,8 and 17 respectively
a). Write down the formula of the compound
formed when calcium reacts with chlorine.
b). State the valences of the three
atoms
c).Given the oxidation state oxygen in
the compound formed when it reacts with
calcium.
d)Give two uses of chorine.
13.The table below shows the formula of
elements P, Q , R and ( not actual symbols) and their chlorides.
|
Element
|
P |
Q |
R |
S |
|
Formula
of chloride |
P
cl |
Q
cl2 |
Rcl3 |
S
cl5 |
a).State the group to which each of
elements belong.
b).Indentify one element which is a
non-metal.
c).Write down the formula of the oxide
of element R.
14. Element T to period 3 and Group v/of
the periodic table
a) Draw diagram to show the electronic
structure of element T.
b).Determine its atomic number.
15. Element X (not actual symbol) has
atomic number 19 and mass number 39.
a). State the number of neutrons in
element X
b).Give the oxidation number of element
X.
16. The table below gives the number of
protons and neutrons in element G ,H,Iand T (not actual symbols)
|
Element
|
G |
H |
I |
J |
|
Number
of protons |
3 |
17 |
19 |
19 |
|
Number
of neutrons |
4 |
20 |
18 |
22 |
a.)Which of the
atoms are isotope of the same element?
b).Which have the atoms have the some
mass number?
c).Write the formula of the compound d
formed between G and H.
17.Neon(ne) has three isotope 20Ne ( abundance
90.3%) 21 Ne ( abundance 0.3%) and
(22Ne (abundance 9.2 %) .
Determine the relative atomic mass of neon
18. Give the oxidation number of the
following substance
a).Fe
b).Cl2
c).Sulphur in sulphur (iv) oxide (so2)
d).Manganese in permanganate ion (mnO4-)
19. The table below shows the valences
of some element and radicals.
|
Element/
Radical |
Valency |
|
Na |
1 |
|
Al |
3 |
|
Cu |
2 |
|
Pb |
2 |
|
Fe |
3 |
|
So4 |
2 |
|
Cl |
1 |
|
No3 |
1 |
|
Co3 |
2 |
Use the information in the table to
answer the following questions;
a)Write the formula of the compound
formed by the following pairs:-
i).Na and SO4
ii).Cu and Cl
iii).Fe and NO3
iv).Al and SO4
v).Pb and Co3
b).Give the valence of each of the
elements or radicals the following chemical compounds
i).Ca3(PO4)2
ii).CuCl
iii) Mg3N2
iv).NaHCO3
v).Zn(No3)2
20.(a) Mention at least four physical properties of alkaline earth
metals.
(b) Mention the chemical properties of
alkaline earth metals.
(c) An atom has mass number of Jb
and an atomic number 26 calculate:-
i).What is the neutron number of the element?
ii).How many electrons are there in an atom of the element|
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