CONTENT STANDARD:

The learner demonstrates understanding of the identity of a substance

according to its atomic structure.

COMPETENCY:

S8MT-IIIe-f-10 Determine the number of protons, neutrons, and electrons in

a particular atom

Photo source:https://biyahengjuansided.files.wordpress.com

Have you ever been to Sampaloc Lake? What are the things that you can

see in the lake? What can you say about the things that you can see around

it? The mountains surrounding it, the people visiting it and even the smallest

rocks that you can see is matter.

made up of very small particles called atom. These atoms are further divided

into three subatomic particles namely the: protons, electrons and neutrons.

Among these subatomic particles, it is the number of protons that make

one element differs from another element. The number of protons is different

for different elements, but all atoms of an element have the same number of

protons in the nucleus.

In this module, you will be able to determine the number of protons, electrons

and neutrons given their atomic number and atomic mass.

Activity

What’s in a Number?

Objectives:

1. Locate the atomic number in a periodic table

2. Identify the subatomic particles associated with mass number

3. Determine the number of protons, neutrons and electrons from the atomic

number and mass number

Materials Needed:

Paper

Periodic table

Procedure:
1. Using the periodic table, look for the atomic number and mass number of

the following elements:

Elements Atomic Number Mass Number

Calcium

Chlorine

Sodium

2. Study the table below. Relate the number of protons, neutrons and

electrons from their atomic number and mass number.

https://image.slidesharecdn.com/atomicstructure

Atoms Number of Number of Number of

Protons Electrons Neutrons

P+ e- n0

Calcium (Ca) 20 20 20

Chlorine (Cl) 17 17 18

Sodium (Na) 11 11 12

3. Now that you already know the atomic number tells the number of protons

and electrons and that the mass number is equal to the sum of protons and

neutrons, complete the table below. Refer to the periodic table in determining

the atomic number and mass number.

Number Number Protons P+ Electrons Neutrons

e- n0

Sulfur

Potassium

Oxygen

Nickel

Iodine

Analysis

1. How did you find the activity?

2. Were you able to determine the number of protons, electrons and

neutrons?

3. How did you get the number of protons? number of electrons? Number of

neutrons?

4. Is it possible for an atom with the same number of protons to have different

number of neutrons?

Abstraction

One characteristic that is common to all atoms of an element is the

number of protons in their nuclei. This number that is unique to a given

have the same number atomic number and the same number of protons in the

nuclei of their atoms.

The atomic number not only give the number of protons in the

atom; it also provides the number of electrons for neutral atom

8 atomic number of a neutral oxygen is 8; it has 8 protons and 8

electrons.

The mass number, A , tells the number of protons plus the number of

neutrons in the atom. There are some atoms that have the same number of

protons but have different number of neutrons, these are called isotopes.

Hydrogen has three isotopes, the protium ( 1H1), deuterium (2H1), and tritium

(3H1). Despite these differences, isotopes have similar chemical and physical

properties. They differ very slightly in physical properties that depend on the

mass. This is because they have identical protons and electrons which are

responsible for the chemical behavior of each element.

Isotopes of Hydrogen

Photo Source: https://upload.wikimedia.org/wikipedia/commons

Symbol Name No. of No. of No. of

Protons Electrons Neutrons

11C Carbon-11 6 6 5
6

12C Carbon-12 6 6 6
6

13C Carbon -13 6 6 7

14C Carbon -14 6 6 8

Application

Answer the following question:

1. Your group won a gold medal in cooking contest in coco festival. If gold is

represented as 197Au79, how many protons and neutrons does gold have?

2. Beneatzky is a popular store of silver accessories in San Pablo City. If the

atomic number of silver is 47 and its atomic mass is 108, how many protons,

electrons and neutrons does it have?

3. Cesium -137 is a very useful isotopes in treating cancer. Determine its

number of protons and neutrons.

Performance Task

Choose one element in the periodic table and look for its atomic

number and mass number. Make your own atomic model which shows the

number of protons, electrons and protons using materials found in your

community. (Examples fruits like bignay, aratiles,seeds). Your model will be

graded using the rubric below.

Information The model includes The model The model

All the facts and includes MOST includes SOME

knowledge of the facts and facts and

topic knowledge of the knowledge of the

topic topic

Presentation The model is well The model is The model is not

presented and all mostly well neat and hard to

the information is presented but understand

easy to understand some information

was difficult to

understand

Construction Appropriate Appropriate Appropriate

Materials materials were materials were materials were

selected and selected and selected

creatively modified there was an

in ways that made attempt at

them even better creative

modification
Closure

References:

Breaking Through Chemistry

Saranay”Sol” M. Baguio and Rose Mary B. Buturan