1. Atom
And Atomic structure

2. Atom: Every substance is made
up of atom

3. •
Atomic theory
Democritus(400BC):
All Substances of tiny indivisible particles called atom.
• John Dalton(1808):
1. All matter consisted of small indivisible particle.
2. Atom of same element are alike
3. Atoms are combined in simple whole number ratios.
 J.J Thomson(1897):
Atom is a sphere of positive matter in which electrons are positioned by electrostatic
forces.
Major portion of the atom is empty.
 Rutherford
The whole mass of the atom is concentrated in the centre of atom called nucleus. The
positively charged particles are present in the nucleus of atom. The electrons revolve
around the nucleus in different circular orbits. Size of nucleus is very small as compare
to the size of atom.

4. Short video on atom
 http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/
fundamentals/

5. Introduction to the Periodic
Table
Atomic Number ● Symbol ● Atomic Weight
Element ● Compound ● Mixture

6. Dmitri menDeleev
Creation of PERIODIC TABLE !

7. PERIODIC TABLE
 Shows all known elements in
the universe.
 Organizes the elements by
chemical properties.

8. How do you read the PERIODIC
TABLE?

9. What is the ATOMIC NUMBER?
o The number of protons
found in the nucleus of
an atom
Or
o The number of
electrons surrounding
the nucleus of an
atom.

10. What is the SYMBOL?
o An abbreviation of
the element name.

11. What is the ATOMIC WEIGHT?
o The number of protons
and neutrons in the
nucleus of an atom.

12. How do I find the number of protons,
electrons, and neutrons in an element
using the periodic table?
o # of PROTONS = ATOMIC NUMBER
o # of ELECTRONS = ATOMIC NUMBER
o # of NEUTRONS = ATOMIC _ ATOMIC
WEIGHT NUMBER

13. Video on periodic table
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa
/fundamentals/theperiodictableact.shtml

14. Google web side to learn
more about periodic table
www.chemicalelements.com/
Home Work
Go to web side and make brief notes of page 1 and 2.
Draw atomic structure and clearly mention number of
electron, proton, and neutron.

15. What is an ELEMENT?
o A substance
composed of a
single kind of atom.
o Cannot be broken
down into another
substance by
chemical or physical
means.

16. What is a COMPOUND?
o A substance in
which two or
more different
elements are
CHEMICALLY
bonded together.

17. What is a MIXTURE?
o Two or more
substances that
are mixed
together but are
NOT chemically
bonded.

18. Element, Compound or
Mixture?

19. Element, Compound or
Mixture?

20. Element, Compound or
Mixture?

21. Element, Compound or
Mixture?

22. Element, Compound or
Mixture?