1. Atoms, Molecules and Ions
H.Imam Rachmat,spd

2. Objectives
To define the meaning of particles of matter (atom, ion and molecule)
To explain the difference of isotope, isotones and isobar
To explain the difference between the element molecule and the compound molecule
To mention some examples of simple molecules in daily life
To give examples of substances that consist of ions

3. Particles of matter Look at the figure !
On grade VII you learned that all matters around us are made up of fundamental matter called ELEMENT.
Element is a simple substance whch cannot be broken down into simpler subtances
Look at the figure !
A piece of iron is composed of a mass of iron atoms

4. What is an atom???
Atom is the smallest unit of an element, having the properties of that element.
Democritus’s model
( the father of atomic theory) Fe Fe Fe Fe Fe Fe Fe
This is atom Fe ( iron )

5. How has the model of the atom changed over time ?
Dalton’s Concept
John Dalton, an English schoolteacher in the early nineteenth century, combined the idea of elements with the earlier theory of the atom.
He proposed the following ideas about matter:
Matter is made up of atoms,
Atoms cannot be divided into smaller pieces,
All the atoms of an element are exactly alike
Different elements are made of different kinds of atoms.
Dalton’s model 1807

6. Thomson’s model 1903 Atom is continuous mass of positive
charge containing
negative electron
Raisin pudding model

7. Rutherford’s model 1903 Atom has a nucleus surrounded by electron
e- e- e- e- e- e-
e e- e-

8. Niels Bohr’s model 1913 Atom has a nucleus. Electrons move
in fixed orbits
around the
nucleus e-
nucleus e- e-

9. Structure of atoms THE STRUCTURE OF ATOMS
Atoms are made up of three subatomic
particles
Protons carry positive charge
Neutrons having no charge
Electrons carry negative charge
The protons and neutrons are tightly bound together to form the central portion of an atom called the nucleus.
The electrons are located outside of the nucleus and thought to move very rapidly throughout a relatively large volume of space surrounding the small but very heavy nucleus.

10. The comparison of particles in atom
charge
Position in atom
Proton
Neutron
electron +1
No charge
- 1
Atom nucleus
Moving around atom nucleus

11. Atomic Mass

12. ISOTOPES
Isotopes are atoms with the same atomic numbers but different mass numbers.
EXAMPLES
Hydrogen
Chlorine
Carbon

13. ISOBAR
Atoms of different elements might have the same mass number.
EXAMPLES
ISOTONES
Atoms of different elements might have the same number of neutron
EXAMPLES

14. Electron Arrangement
According to Bohr, electrons move around the nucleus in fixed orbit or shells
The electron in each shell have different energy level. The shells closes to the nucleus have lower energy levels than those farther away
The biggest atoms can have up to 7 electron shells,
However, each shell can contain only a limited number of electrons. This number depends on their size:
1st shell maximum filled with 2 electrons.
2nd shell maximum filled with 8 electrons.
3rd shell can hold up to 18 electrons, but normally only holds up to 8 to make atom more stable.
4th shell can hold up to 32 electrons but, like the third shell, normally holds only up to 8 to make atom more stable

15. Example of Electron arrangement
Sodium
Σp=11
Σe=11
Σn=12
Electronic Configuration:
2, , 1
1st shell
2nd shell
3rd shell
Electronic Structure
The electron in the outermost shell of an atom are called the outer electron or valency electrons
Sodium has 1 valency electron

17. ions Ion is an atom having electric charge
When atoms lose or gain electrons, they become ions
atom
Loses electrons +
Positive ion _
Negative ion
An atom may gain or lose electrons
Gains electrons

18. Cl Na+ Na Cl- cation – ion with a positive charge
If a neutral atom loses one or more electrons it becomes a cation. Na
11 protons
11 electrons
Na+
11 protons
10 electrons
anion – ion with a negative charge
If a neutral atom gains one or more electrons it becomes an anion. Cl
17 protons
17 electrons
Cl-
17 protons
18 electrons

19. Predicting Ionic Charge
Metals tend to form cations (group 1 and 2)
Non-metals tend to form anions.(group 5, 6, 7 )
Be2+

20. A monatomic ion contains only one atom
Na+, Cl-, Ca2+, O2-, Al3+, N3-
A polyatomic ion contains more than one atom
OH-, CN-, NH4+, NO3-
2.5

21. 1. Why do atoms bond together?
Atoms bond to become more stable, like Noble Gases.

22. 1. Ionic bonds
Ionic bonds are formed by one atom transferring electrons to another atom to form ions.
Ionic Compound – A compound that contains positively charged ions and negatively charged ions. + 

23. BaCl2 barium chloride K2O potassium oxide Mg(OH)2 magnesium hydroxide
Ionic Compounds
often a metal + nonmetal
anion (nonmetal), add “ide” to element name
BaCl2
barium chloride
K2O
potassium oxide
Mg(OH)2
magnesium hydroxide
KNO3
potassium nitrate
2.7

24. Example:   2. Covalent Bonding
Covalent bonds are formed by atoms sharing electrons to form molecules.
This type of bond usually formed between two non-metallic elements.(between 2 gass)
Example:
Two hydrogen atoms (1) form the molecule of the element hydrogen H2
Two chlorine atoms (2.8.7) form the molecule of the element chlorine Cl2 +  + 

25. Another examples of covalent bond:
Oxygen (o2)
Water (H2O)
Ammonia (NH3)
Carbon Dioxide (CO2)

26. Comparison properties of ionic and covalent compound
Ionic Compound
Covalent Compound
Electrical Conductivity
Conduct electricity when dissolved in water
Does not conduct electricity in any state
Melting point and boiling point
High
Low
Solubility in water
Mostly soluble
Mostly insoluble

27. C. Molecule
A molecule is made up of two or more atoms chemically combined together.
Molecules of Element
Molecules are made up of the same kinds of atoms
Molecules of Compounds
Molecules are made up of two or more different kinds of atoms

28. MOLECULES OF ELEMENT
MOLECULES OF COMPOUND

29. The using of ions and molecules in chemical product in daily life
Composer
Product
Polyvinyl Chloride (PVC)
Water pipe, tile
Polyetilene
Carpet, laboratory apparatus
Isoprene (C5H8) and polystyrene
Rubber
Sucrose (C12H22O11)
Sugar, Syrup
Ionic compound NaCl
Table salt
Ion-ion (Cl-, Na+,Mg 3+, Ca2+)
Isotonic drinks