3. Henry Mosely

4. What are the three sub-
atomic particles of the
atom?

5. How do you call the
positively charged
particles?

6. How do you call the
negatively charged
particles?

7. The particles that were last to
be discovered because it is
uncharged.

8. LET’S ENTER THE
INVISIBLE WORLD !!

10. How do we
determine the
number of
protons, neutron
and electrons?

11. The Helium Atom

12. CHEMQUESTStructure of the
Atom

13. Information: Structure of the
Atom
Note the following symbols: (they
are not to scale)
= proton (positive charge)
= electron (negative charge)
= neutron (no charge)

14. The following three diagrams
are hydrogen atoms:
1
1H 1
2H 1
3H

15. The following three
diagrams are carbon
atoms:
12
6C 13
6C 14
6C
6 protons,6 neutrons 6 protons,7 neutrons 6 protons,8 neutrons

16. Notice the type of
notation used for atoms:
Z
A
X
x= CHEMICAL SYMBOL OF ELEMENT
Z= ATOMIC NUMBER
A= MASS NUMBER

17. 6
12C, 6
13C , 6
14 C are notations
that represents isotopes of carbon.
1
1 H , 1
2H , 1
3 H are notation that
represents isotopes of hydrogen.

18. 1.How many protons are there in the
following: 1
1
H?, 1
2
H?, 1
3
H?
CRITICAL THINKING QUESTIONS:
1 proton for 1
1
H
1 proton for 1
2
H
1 proton for 1
3
H

19. 2.How many neutrons are found in each of the
following: 1
1 H, 1
2 H, 1
3 H?
0 neutron for 1
1 H
1 neutrons for 1
2 H
2 neutrons for 1
3 H
CRITICAL THINKING QUESTIONS:

20. 3.How many electrons are found in each of
the following: 1
1 H?,1
1 H?,1
1 H?
1 electron for 1
1H
1 electron for 1
2H
1 electron for 1
3H
CRITICAL THINKING QUESTIONS

21. 4.What structural characteristics
do all hydrogen atoms have in
common?
They have the same atomic
number
CRITICAL THINKING QUESTIONS

22. 5. What structural
characteristics do all carbon
atoms have in common?
They have the same atomic number
CRITICAL THINKING QUESTIONS

23. 6. What does the mass number
tell you?
It tells the number of protons and neutrons in an atom
Can you find it on the periodic table
Yes, it is only express in atomic mass
CRITICAL THINKING QUESTIONS

24. 7.What doe the atomic number tell
you?
Yes.
It tells the number of protons in an atom.
Can you find it in the periodic table?
CRITICAL THINKING QUESTIONS

25. 8. Define the term isotope.
Isotopes is an atom having the same
atomic number but differ in mass
number.
CRITICAL THINKING QUESTIONS

26. 9. How does one isotope of
carbon differ from another
isotope of carbon?
One isotope of carbon is differ in the
number of neutrons from the other
isotope of carbon.
CRITICAL THINKING QUESTIONS

27. IsotopesThe atoms of an element
having the same atomic
number but different mass
number due to difference
in the number of neutrons

28. Mass Number
It refers to the sum of
the numbers of
protons and neutrons
in an atom

29. Atomic Number
It is a unique number of
each element that
corresponds to the
number of protons

30. SKILL PRACTICE
30
65Zn
?Protons
? Electrons
? neutrons
Answer
a. 30
b. 3o
c. 35

31. 1. An atom has a mass number of 43
and it also has 21 as atomic number.
a) How many protons does this
atom have?
b) How many electrons does this
atom have?
c) How many neutrons does this
atom have?
SKILL PRACTICE

32. Answer
a. 21
b. 21
c. 22

35. SYMBOL # OF
PROTONS
# OF
ELECTRONS
# OF
NEUTRONS
ATOMIC
NUMBER
MASS
NUMBER
1. 13
27 Al
2.
35
80Br
QUIZ

36. SYMBOL # OF
PROTONS
# OF
ELECTRONS
# OF
NEUTRONS
ATOMIC
NUMBER
MASS
NUMBER
1. 13
27 Al
13 13 14 13 27
2.
35
80Br
QUIZ

37. SYMBOL # OF
PROTONS
# OF
ELECTRONS
# OF
NEUTRONS
ATOMIC
NUMBER
MASS
NUMBER
1. 13
27 Al
13 13 14 13 27
2.
35
80Br 35 35 45 35 80
QUIZ

39. SEE YOU