Download Nucleon number

MATTER
Learning Outcome
At the end of this topic, students should be
able :
(a) Identify and describe proton, electron
and neutron as subatomic particle.
(b) Define proton number, Z, nucleon
number, A and isotope. Write isotope
notation.
INTRODUCTION
• Matter
Anything that occupies space and has
mass.
e.g air, water, animals, trees,
atoms, …..
• All matter consist of tiny particles
called atoms
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
1) Identify and describe protons, electrons and neutrons as sub-atomic particles
This page will revises the simple ideas about atomic structure that you have come
across in an introductory chemistry course (i.e. SPM). You need to be confident
about this before you go on to the more difficult ideas about atom.
THE SUB-ATOMIC PARTICLES
An atom is the smallest unit of a chemical
element/compound.
In an atom, there are three subatomic particles:
Proton (p)
Neutron (n) Packed in a small nucleus
Electron (e)
Move rapidly around the nucleus of an atom
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Modern Model of the Atom
electron
-
Proton
nucleus
+
( positive charge)
+
Neutron (neutral)
• Electrons move around the region of the atom.
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
Proton no.
Nucleon no.
Isotopes
Nucleon number or
mass number
A
Z
X
Atomic symbol
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
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TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
Proton no.
Nucleon no.
Isotopes
Nucleon number or
Proton
number (Z) is the number of protons
mass number
in the nucleus of each atom of an element.
Also known as atomic
number
A
Atomic symbol
In a neutral atom, the number of protons is
equal to the number
Z of electrons.
X
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
Proton no.
Nucleon no.
Isotopes
Nucleon number or
mass number Nucleon number (A) is the total number of
neutrons and protons present in the nucleus
of an atom
A of an element.
X
Atomic symbol
Also known as mass number
Z
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
Proton no.
Nucleon no.
Nucleon number or
mass number
Isotopes
Isotopes, atoms that have the same proton
number but different nucleon number.
Ai.e. Hydrogen has three
Atomicisotopes
symbol
2
1
3
Z
H
H
1
1
1H
X
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
Proton no.
Nucleon no.
Nucleon number or
mass number
Isotopes
Nucleon number = proton no. + no. of neutrons.
So, the number of neutrons is equal to the different
between the nucleon no. & the proton no. or ( A-Z).
Ex. Nucleon no. of fluorine is 19 & proton no. is 9.
Thus, the no. of neutrons in fluorine is 19 – 9 = 10.
Note: proton no., nucleon
no. &symbol
no. of neutrons all
Atomic
must be positive integers (whole numbers)
A
Z
X
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
Proton no.
Nucleon no.
Nucleon number or
mass number
Isotopes
In a neutral atom the no. of protons is equal to the
no. of electrons, so the proton no. also indicates the
no. of electrons present in the atom.
A For example, the proton
Atomic symbol
no. of nitrogen is 7. This
each neutral nitrogen atom has 7
Z means thatprotons
and 7 electrons.
X
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
The X represent of atom of an element. For
example atom of uranium with nucleon numbers of
235 and proton numbers of 92. So the uranium can
Nucleon no.
beIsotopes
denoted as:-
Proton no.
235
92
U
Nucleon number or
mass number
A
Z
X
Atomic symbol
Proton number or
atomic number
Pre-test
Example
Exercise
Past year
Question
Ex:
Number of protons = proton number
= 13
Number of neutrons = nucleon number – proton number
= 27 - 13
= 14
Number of electron = proton number – charge carried by
species
= 13 – ( +3)
= 10
Q: determine the number of proton, neutron
and electron in the following species.
solution
90
38
Sr
Sr
Number of protons = proton number
= 38
Number of neutrons = nucleon number – proton number
= 90 – 38
= 52
Number of electron = proton number (species is neutral)
= 38
35
17
Cl-
Number of protons = proton number
= 17
Number of neutrons = nucleon number – proton number
= 35 – 17
= 18
Number of electron = proton number – charge carried by
species
= 17 – (-1)
= 18
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
1. State the sub-atomic particles of an atom?
2. Define proton numbers and nucleon numbers?
3. What is isotopes? Use hydrogen as an example.
ANSWER
1. Protons, electrons & neutrons
2. Proton numbers = number of protons in the nucleus of an atom
Nucleon numbers = total no. of protons & neutrons in atom
3. Isotopes = atoms that have the same no. of protons but have
different nucleon numbers.
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
1. Give the number of protons, neutrons and electrons in each of the following
species:
(a)
17
8
O
(b)
199
80
Hg
(c)
200
80
Hg
ANSWER
* Recall that the superscript denotes nucleon number & the subscript denotes
proton number.
(a) Proton number = 8, so there are 8 protons. Nucleon number = 17, so the
number of neutrons is 17-8 = 9. The number of electrons is the same as
the number of protons, that is 8.
(b) Proton numbers = 80, so there are 80 protons. Nucleon number = 199, so the
number of neutrons is 199-80 = 119. The number of electrons = 80.
(c) Number of protons = 80. Number of neutrons, 200-80 = 120. Number of
electrons = 80.
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
1. Isotopes of an element are having
A the same nuclear charge
B similar physical properties
C the same number of neutrons
D the same relative abundance
2. All the following statements are true EXCEPT
A Nucleus is the positively charged centre of an atom
B Protons number indicates the number of protons in an atom
C Isotopes are atoms of the same element but with different nucleon number
D Nucleon number is the total number of electrons and protons in an atom
ans
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
1. Isotopes of an element are having
A the same nuclear charge
B similar physical properties
C the same number of neutrons
D the same relative abundance
2. All the following statements are true EXCEPT
A Nucleus is the positively charged centre of an atom
B Protons number indicates the number of protons in an atom
C Isotopes are atoms of the same element but with different nucleon number
D Nucleon number is the total number of electrons and protons in an atom
next
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
3. Which of the following is a pair of isotopes?
A 13858J and 13860K
B 7432L and 7533M
C 8336N and 8436O
D 23592P and 23994Q
4. Which of the following species has 24 neutrons?
A 24Mg
B 45Sc
C 51V
D 52Cr
ans
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
3. Which of the following is a pair of isotopes?
A 13858J and 13860K
B 7432L and 7533M
C 8336N and 8436O
D 23592P and 23994Q
4. Which of the following species has 24 neutrons?
A 24Mg
B 45Sc
C 51V
D 52Cr
next
TOPIC 1: MATTER
SUB TOPIC: Atoms and Molecules
Objective:
At the end of the lesson, you should be able to:
2) Define proton number, nucleon number and isotopes
WELL DONE!
Try some past paper questions