This document discusses isotopes and their properties. It defines isotopes as forms of the same element that have different numbers of neutrons but the same number of protons. It provides examples of carbon isotopes and explains that isotope notation specifies the element name or symbol followed by the mass number. Isotopes can be naturally occurring or artificially made, and they have various medical and dating uses. The document also includes questions to test the reader's understanding of isotopes.

3. REVIEW OF THE PREVIOUS LESSON
Direction: Unscramble the following words in each
sentence.
1. ( ntopor) refers to the positively charged particles of
an atom.
2. The particle of an atm that is neither positive nor
negative is (tnruneo).
3. The smallest particle of matter is called (oamt).
4. (tneelorc) is a particle of matter that carries a
negative charge.
5. (nsuulec) is found at the center of the atom that
carries protons and neutrons.

5. REVIEW OF THE PREVIOUS LESSON
Direction: Unscramble the following words in each
sentence.
1. ( ntopor) refers to the positively charged particles of
an atom.
2. The particle of an atm that is neither positive nor
negative is (tnruneo).
3. The smallest particle of matter is called (oamt).
4. (tneelorc) is a particle of matter that carries a
negative charge.
5. (nsuulec) is found at the center of the atom that
carries protons and neutrons.
Protons
neutron
atom
electron
nucleus

6. SPOT THE DIFFERENCE

8. WHAT IS ISOTOPES?
• Isotopes are each of two or more forms of the
same element that contain equal numbers of
protons but different numbers of neutrons in
their nuclei, and hence differ in relative atomic
mass but not in chemical properties; in
particular, a radioactive form of an element,
• Atoms of the same element that have different
masses are called isotopes.

9. • Isotopes are
notated in multiple
ways. Most
commonly, they
are specified by
the name or
symbol of the
particular element,
immediately
following by a
hyphen and the
mass number.
WRITING ISOTOPES

10. • Isotopes can either
form spontaneously
(naturally) through
radioactive decay of
a nucleus. ) or
artificially by
bombarding a
stable nucleus with
charged particles
via accelerators or
neutrons in a
nuclear reactor.
HOW DOES ISOTOPES FORM?

11. • Isotopes can
also be defined
in standard, or
"AZE", notation
where A is the
mass number, Z
is the atomic
number, and E is
the element
symbol.
WRITING ISOTOPES

12. • Isotopes are
used in a few
different areas.
14C is an
isotope of the
carbon atom
use in carbon
dating, which
helps scientist
date objects
like fossils.
USES OF ISOTOPES

13. • Isotopes are
also used
medical field
like isotopes of
iodine, Iodine-
131 and iodine-
125, which are
used in
radiation
therapy for
thyroid
diseases.
USES OF ISOTOPES

15. DIRECTIONS: READ AND ANALYZE THE QUESTIONS
BELOW.
Here are three isotopes of an element: 12
6 C 13
6 C 14
6 C
1. The element is __________.
2. The number 6 refers to the _____________
3. The number 12, 13, 14 refers to the __________________.
4. How many proton and neutron are in the first isotopes? __________.
5. How many proton and neutron are in the second isotopes? __________.
6. How many proton and neutron are in the third isotopes? __________.

18. DIRECTIONS: READ AND ANALYZE THE QUESTIONS
BELOW.
Here are three isotopes of an element: 12
6 C 13
6 C 14
6 C
1. The element is __________.
2. The number 6 refers to the _____________
3. The number 12, 13, 14 refers to the __________________.
4. How many proton and neutron are in the first isotopes? __________.
5. How many proton and neutron are in the second isotopes? __________.
6. How many proton and neutron are in the third isotopes? __________.
12
Atomic Number
Mass Number
Carbo
n
13
14

20. DIRECTION: COMPLETE THE TABLE BELOW.
Isotope
name
Atomic
no.
Mass
no.
No. of
protons
No. of
neutron
s
No of
electron
s
Uranium
-235
92 235 92
Uranium
-238
238
Boron-
10
10 5
Boron-
11
11 5

23. DIRECTION: COMPLETE THE TABLE BELOW.
Isotope
name
Atomic
no.
Mass
no.
No. of
protons
No. of
neutron
s
No of
electron
s
Uranium
-235
92 235 92 143 92
Uranium
-238
92 238 92 146 92
Boron-
10
5 10 5 5 5
Boron-
11
5 11 5 6 5

25. DIRECTION: CHOOSE THE LETTER OF THE BEST ANSWER. WRITE
THE CHOSEN LETTER ON A SEPARATE SHEET OF PAPER.
1. What do you call two or more forms of the same element that contain
equal numbers of protons but different numbers of neutrons in their
nuclei?
A Atoms b. element c. nuclei d. isotopes
2 . If carbon-14 is an isotope, how many protons does it have?
a. 7 b. 6 c. 8 d. 10
3. If carbon-14 is an isotope, how many neutrons does it have?
a. 7 b. 6 c. 8 d. 10
4. If carbon-14 is an isotope, how many electrons does it have?
a. 7 b. 6 c. 8 d. 10
5. What isotopic element is used to treat thyroid diseases?
a. Carbon b. iodine c. hydrogen d. uranium

27. DIRECTION: CHOOSE THE LETTER OF THE BEST ANSWER. WRITE
THE CHOSEN LETTER ON A SEPARATE SHEET OF PAPER.
1. What do you call two or more forms of the same element that contain
equal numbers of protons but different numbers of neutrons in their
nuclei?
A Atoms b. element c. nuclei d. isotopes
2 . If carbon-14 is an isotope, how many protons does it have?
a. 7 b. 6 c. 8 d. 10
3. If carbon-14 is an isotope, how many neutrons does it have?
a. 7 b. 6 c. 8 d. 10
4. If carbon-14 is an isotope, how many electrons does it have?
a. 7 b. 6 c. 8 d. 10
5. What isotopic element is used to treat thyroid diseases?
a. Carbon b. iodine c. hydrogen d. uranium