Chapter 2: Atomic structure
electron shell energy level
=
e pin e pt-positive m= 1
no -neutral m=
e-negative m =
Atomic number (protons) A
Mass number (protons neutrons) + A Z
Relative atomic # mass
mass number
5The relative atomic mass is the mass reported in
periodic table Mass number is the
. number of protons
and neutrons of specific isotopes
Cotion positive-
in
Anion-negative ion
25 2+
p+, n 13
1782 pin
12 Mg
=
e 12 2 = 10 8 + 2 = 10
=
=
e
-
Isotopes atoms of the same element with the same
-
number of protons but different number of neutrons.
,
H in H
I
pt I I I
N O I 2
-
The same chemical properties ,
because of the same
no . of valence electrons
-
The physical properties are different ,
due to differen
masses
, Carbon dating -
we can find the age of a fossil by
measuring the ratio between "C atom and "Catom
"C is changed to "N due to its half life time
Topic Relative
: atomic masses
Mass spectrometer -
used to find relative atomic mass
of substances
-
is used to determine percentage composition of
STEPS :
isotopes of element ionization : sample bombarded
*
78 6
with
high-energy/speed electrons
acceleration electric field
.
:
deflection :
magnetic field
abundance
(%)
10 1
11 3
.
atomic mass
.
Y
M 7
B- ratio
24 25 26 charge
- -
Mg ribbon :
-
1000
786
atoms
atoms A 24 =
-
101 atoms A = 25
-
113 atoms A =
26
+1, " A , t... + In "An
Ar 100 %
Ar = 78 6 x24 +
10) x 25 +
11.3x26 24 33
.
=
.
100
electron shell energy level
=
e pin e pt-positive m= 1
no -neutral m=
e-negative m =
Atomic number (protons) A
Mass number (protons neutrons) + A Z
Relative atomic # mass
mass number
5The relative atomic mass is the mass reported in
periodic table Mass number is the
. number of protons
and neutrons of specific isotopes
Cotion positive-
in
Anion-negative ion
25 2+
p+, n 13
1782 pin
12 Mg
=
e 12 2 = 10 8 + 2 = 10
=
=
e
-
Isotopes atoms of the same element with the same
-
number of protons but different number of neutrons.
,
H in H
I
pt I I I
N O I 2
-
The same chemical properties ,
because of the same
no . of valence electrons
-
The physical properties are different ,
due to differen
masses
, Carbon dating -
we can find the age of a fossil by
measuring the ratio between "C atom and "Catom
"C is changed to "N due to its half life time
Topic Relative
: atomic masses
Mass spectrometer -
used to find relative atomic mass
of substances
-
is used to determine percentage composition of
STEPS :
isotopes of element ionization : sample bombarded
*
78 6
with
high-energy/speed electrons
acceleration electric field
.
:
deflection :
magnetic field
abundance
(%)
10 1
11 3
.
atomic mass
.
Y
M 7
B- ratio
24 25 26 charge
- -
Mg ribbon :
-
1000
786
atoms
atoms A 24 =
-
101 atoms A = 25
-
113 atoms A =
26
+1, " A , t... + In "An
Ar 100 %
Ar = 78 6 x24 +
10) x 25 +
11.3x26 24 33
.
=
.
100
