Basic Science and Technology – Primary 6 Weekly Short Class Lesson Notes for Second Term

WEEK 8 – ATOM AND ELEMENTS | FIRST 20 ELEMENTS OF PERIODIC TABLE

MEANING OF ATOM

An atom is the smallest particle of matter that cannot be seen with the naked eye. Atoms make up everything around us – air, water, plants, animals, and objects.

Atoms combine to form molecules.

Example – Water is made of atoms of hydrogen and oxygen.

 

Elements of an Atom

An atom is made up of three main subatomic particles called elements of an atom:

a) Protons

• Positively charged particles (+)

• Found in the nucleus (center) of the atom

• Determine the identity of an element

b) Neutrons

• Neutral particles (no charge)

• Also found in the nucleus

• Help stabilize the atom

c) Electrons

• Negatively charged particles (-)

• Move around the nucleus in electron shells

• Involved in chemical reactions and bonding

 

Diagram of an Atom (Simple)

Electron (-)

 o

↓

      [ Nucleus ]

      /                \

         Proton (+)       Neutron (0)

Summary – An atom is the smallest particle of matter. It is made of protons (+), neutrons (0), and electrons (-).

 

MEANING OF ELEMENTS

An element is a pure substance made of only one type of atom. Elements cannot be broken down into simpler substances by ordinary chemical methods.

Each element has a unique symbol in chemistry. The table below shown,

First 20 Elements of the Periodic Table

Atomic Number	Element Name	Symbol
1	Hydrogen	H
2	Helium	He
3	Lithium	Li
4	Beryllium	Be
5	Boron	B
6	Carbon	C
7	Nitrogen	N
8	Oxygen	O
9	Fluorine	F
10	Neon	Ne
11	Sodium	Na
12	Magnesium	Mg
13	Aluminium	Al
14	Silicon	Si
15	Phosphorus	P
16	Sulphur	S
17	Chlorine	Cl
18	Argon	Ar
19	Potassium	K
20	Calcium	Ca

 

10 MULTIPLE CHOICE QUESTIONS AND ANSWERS ON ATOM AND ELEMENTS | FIRST 20 ELEMENTS OF PERIODIC TABLE

INSTRUCTION – Choose the correct answer from the options A – D. 

1. An atom is ______. 

A. the largest part of matter

B. the smallest particle of matter

C. a mixture

D. a liquid

 

2. Everything around us is made up of ______. 

A. atoms

B. water

C. air

D. soil

 

3. An element is a substance made of ______. 

A. different types of atoms

B. two or more molecules

C. only one type of atom

D. mixed substances

 

4. Which of the following is an element?

A. Water

B. Salt

C. Sugar

D. Oxygen

 

5. Which particle has a positive charge?

A. Electron

B. Neutron

C. Proton

D. Atom

 

6. Electrons are found ______. 

A. in the nucleus

B. outside the nucleus

C. inside protons

D. inside neutrons

 

7. The periodic table is a chart that shows ______. 

A. only metals

B. only gases

C. all known elements

D. only liquids

 

8. The symbol for Oxygen is ______. 

A. Ox

B. Og

C. Oy

D. O

 

9. Elements in the periodic table are arranged according to ______. 

A. size

B. colour

C. atomic number

D. weight only

 

10. Which of these is NOT an element?

A. Carbon

B. Iron

C. Gold

D. Water

 

FILL IN THE GAP QUESTIONS

11. The smallest part of an element that can exist is called an ______.

12. An element is a substance made up of only ______ type of atom.

13. Atoms are made up of protons, neutrons, and ______.

14. The Periodic Table is a chart that shows all known ______.

15. Each element in the Periodic Table has a special name and a ______.

 

SHORT ANSWER QUESTIONS

16. What is an atom?

17. What is an element?

18. Name two parts of an atom.

19. What is the Periodic Table?

20. Mention one use of the Periodic Table.

 

ANSWER KEYS 

1. B 2. A 3. C 4. D 5. C 6. B 7. C 8. D. 9. C 10. A 11. atom 12. one 13. electrons 14. elements 15. symbol

16. An atom is the smallest unit of an element.

17. An element is a pure substance made of only one type of atom.

18. Proton and electron.

19. The Periodic Table is a chart that arranges elements in an orderly way.

20. It helps scientists study and identify elements easily.