01.
|
i |
Ii |
iii |
iv |
v |
|
A |
A |
D |
C |
B |
02.
i)
Matter is anything that has weight or mass and occupies a space.
ii)
An atom is the smallest particle of an element that has all the
chemical properties of that element.
iii)
Electronic configuration is the arrangement of electrons in
different shells of an atom.
iv)
Atomic number is the number of proton in an atom.
v)
Relative Atomic Mass (RAM) is the mass of an atom obtained by
comparing it with the arbitrary mass of a carbon-12 atom.
03. (a) Modern concepts of Dalton’s Atomic
Theory
§
Atoms
can be created or destroyed by means of nuclear reactions
§
Atoms
of one element (isotopes) differ slightly in mass
§
Atom is
made up of smaller sub-atomic particles (proton, neutron and electron)
§
Atoms
of different elements may combine in many different ratio to form complex
compounds.
(b) Properties of sub-atomic particles
i) Proton
o
It is a
positively charged particle
o
It is
found in the nucleus of an atom
o
Its
symbol is P
o
Its
charge is +1
o
Its
real mass is 1.16726 x 10-24 g
ii) Neutron
o
It is
neutral particle of an atom (it has no charge)
o
It is
found in the nucleus of an atom
o
Its
symbol is n
o
Its
charge is 0
o
Its
real mass is 1.6750 x 10-24 g
iii) Electron
o
It is a
negatively charged particle of an atom
o
It is
found around the nucleus
o
Its
symbol is e-1
o
Its
real mass is 9.109 x 10-28 g
04. (a) Isotopes are the atoms of the same
element which have the same atomic number but different atomic mass.
(b) From Relative Atomic mass (RAM) = ∑ (Abundance of atom x
atomic mass)
RAM =
= 35.5
o
The
Relative Atomic mass of Chlorine is 35.5
05. (a) 4924Q ,
From, A = P + n
Where:
A = Atomic number/ atomic mass
P = Atomic number/ number of proton
n = number of neutron
49 = 24 + n, n = 49 -24 à 25
i.
The
neutron number is 25
ii.
The number
of electron = number of proton = 24
(b) 15M = 2:8:5, element M belongs to Group V
and period 3
