Chemistry Form 4 Notes – Chapter 2: Atomic Structure[Atom]

The Atomic Structure

 

A History Of An Atom

John Dalton  info

Imagined the atom as a small indivisible ball similar to a very tiny ball.

 

J.J Thomson info

He discovers the electron.

He described the atom as a sphere/cloud of positive charge which contains a few negatively-charged particles called electrons.

Ernest Rutherford info

He discovers the proton.

He suggested that protons are concentrated in the center of the atom called the nucleus, with a cloud of electrons surrounding the nucleus

 

Niels Bohr   info

He suggested that the electrons are moved in definite orbits surrounding the nucleus.

 

James Chadwick info

He discovered the neutron. He suggested that nucleus consists of protons and neutrons, with the nucleus surrounded by electron shells.

 

 The Atom SONG

The Properties Of The Subatomic Particles:

PROTONS, ELECTRONS AND NEUTRONS

Subatomic particle	Symbol	Relative mass	Charge	Location
Proton	p	1	+1	In the nucleus
Electron	e	1/1840	-1	In orbits around the nucleus
Neutron	n	1	0	In the nucleus

First 20 Element:

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

Protons Number and Nucleon Number

1. All elements are made up of small invisible particles called atoms.
2. The proton number (also known as the atomic number) of an atom is the number of protons in the nucleus of an atom.
3. The nucleon number (also known as mass number)    of an atom is the sum/total of the number of protons and neutrons in the atom.

 
 Remember!!!!

Nucleon number =   Number of protons + Number of neutrons

 

Isotopes and Their Importance

The isotopes of an element are the atoms of that element which contain a same number of protons, but a different number of neutrons.

 Example:

 

The uses of isotopes in daily life

 

Field	Isotopes applications
Medical	·      Gamma rays from cobalt- 60 are used to kill cancer cell without surgery in patient. This treatment is known as radiotherapy. ·      Medical instrument are sterilized using gamma rays. ·      Radioactive materials such as iodide-131 are injected into patients to detect malfunction of thyroid glands.
Archeology	·      Radioisotope carbon -14 is used to study the age of ancient artifacts.
Agricultural	·      Carbon -14 is used to study the passage of carbon in photosynthesis of green plants.
Industrial	·      Isotope sodium-24 is used to detect leakage of underground  pipes.

 The ATOMIC Structure
 

You must know the electronic structures for the first 20 elements in The Periodic Table

 

 

The electron arrangement of elements with proton number 1 to 20.

 

Element	Number of neutrons	Number of protons	Number of electrons	Nucleon number	Electron arrange-ment	Number of valence electrons
Hydrogen	0	1	1	1	1	1
Helium	2	2	2	4	2	2
Lithium	4	3	3	7	2.1	1
Beryllium	5	4	4	9	2.2	2
Boron	6	5	5	11	2.3	3
Carbon	6	6	6	12	2.4	4
Nitrogen	7	7	7	14	2.5	5
Oxygen	8	8	8	16	2.6	6
Fluorine	10	9	9	19	2.7	7
Neon	10	10	10	20	2.8	8
Sodium	12	11	11	23	2.8.1	1
Magnesium	12	12	12	24	2.8.2	2
Aluminum	14	13	13	27	2.8.3	3
Silicon	14	14	14	28	2.8.4	4
Phosphorus	16	15	15	31	2.8.5	5
Sulphur	16	16	16	32	2.8.6	6
Chlorine	18	17	17	35	2.8.7	7
Argon	22	18	18	40	2.8.8	8
Potassium	20	19	19	39	2.8.8.1	1
Calcium	20	20	20	40	2.8.8.2	2

 so...Hopefully anda telah faham tentang atom...Pastikan anda mengingat 20 unsur pertama ini. Anda juga perlu mahir dalam melukis struktur atom tersebut.

ok...jom kita rehat jap, dengar lagu 20 unsur pertama:...jumpa anda di BAB 3