Defining the Atom

1. Defining the Atom Hadi Syed

2. History • In Ancient Greece a man named Democritus figured out that every single thing in the universe must be made up of tiny particles that can’t be cut anymore • He called these particles “atoms”, which in Greek means “uncuttable”

3. What is an atom? • An atom is the smallest particle of an element

4. What’s inside an atom? • Protons and neutrons are made up of three quarks each • Electrons are a kind of lepton • Quarks and leptons are fundamental particles—the smallest particles in the Universe

5. Inside an atom

6. How big is atom? • The radius of a typical atom is one tenth of a billionth of a meter • A cube of sugar contains as many atoms as there are stars in the Universe

7. Subatomic particles • The particles smaller then atom are called subatomic particles

8. Structure of an Atom

9. Center • At the center of the atom is a core called a nucleus, which is made up of these subatomic particles called protons and neutrons

10. Nucleus • The nucleus of an atom contains protons and neutrons • The nucleus carries a positive electrical charge

11. Electrons • Moving around the nucleus at incredible speeds are tiny particles called electrons • Electrons move around outside the nucleus

12. Electrical Charge • Each electron has a negative electrical charge • Each proton has a positive electrical charge • The charge of a proton and an electron are equal in size, yet opposite in sign

13. Neutral Neutron • Each neutron is electrically neutral • Protons and neutrons are about the same size as each other and are much larger than electrons

14. There are over 100 different kinds of atoms

15. Chemical Reaction • Electrons are easier to add or remove from an atom than a proton or neutron • Chemical reactions largely involve atoms or groups of atoms and the interactions between their electrons

16. Molecules • When atoms combine together they form molecules

17. Atomic Universe • By combining these atoms in different ways, we can make anything in the universe

18. Can you see an atom? • Atoms are so tiny that they can’t be seen, even with the most powerful microscope

19. Gold Atoms

20. Assalamualaikum

21. Pictures • www.ehs.utoronto.ca - 1006 × 443 • www.universetoday.com - 300 × 250 • www.exo.net - 300 × 300 • www.exo.net - 591 × 565 • Clip art

22. Sources Elementary Atomic Structure by Gordon Kemble Wood gate · Clarendon Press http://profmokeur.ca/chemistry/history_of_the_atom.htm All About Atoms All Atoms Atomic Alchemy: Nuclear Processes