2. How are atoms studied? Atoms are the building blocks of matter Atoms are too small in size to study easily Size of Earth : soda can = soda can : atom

3. Who studied the atom? Studied by many scientists for centuries –Democritus (400 BC) – phrase “atomos” –Rutherford (1911) – nucleus (gold foil expt) –Moseley (1913) – X-rays to find atomic # –*Bohr (1913) – planetary model of the atom –*Schrödinger (1923) – electron cloud model

5. I’m an electron! I’m a proton! I’m a neutron!

6. I was walking along and I saw these two. I was telling jokes to the neutron. The proton and I were having fun.

7. They looked so happy there together. I was p o s i t i v e l y charged! I couldn’t have amassed more happiness.

8. The proton looked happy, so I wandered closer. I could see the electron coming near. The who? Huh?

9. They were HUGE next to me! The electron was so cute! Like a speck of dust, or something…

10. I didn’t want to seem obvious, so I kept walking. Around and around the electron goes. Hey electron, you’re making the proton dizzy.

11. The proton seems so happy with the neutron. I’m having fun, but I still notice the electron. It won’t bother me if the electron hangs around.

12. I guess I’ll just wander around out here. I’m happy hanging out here. The center is cool, but sometimes it can be a “Bohr”.

13. Electrons circle around the nucleus of an atom. Protons are a main part of the nucleus of an atom. Neutrons also hang out in the nucleus of an atom.

14. Electrons have a negative charge.  Protons have a positive charge. + Neutrons have no charge. 0

15. Electrons are little and have a mass of almost zero. Protons are big and have a mass of one. Neutrons are also big and have a mass of one.

18. What is the structure of an atom? Nucleus – center of the atom –Home of Protons and Neutrons –Proton Has a positive (+) charge Has a relative mass of 1 Determines the atomic number Found inside the nucleus

19. What is the structure of an atom? –Neutron Has no (0) charge Has a relative mass of 1 Determines the isotope –Isotopes are two of the same element with different masses Found inside the nucleus

20. What is the structure of an atom? Electron –Has a negative (-) charge –Has a relative mass of 0 (zero) –Determines the ion –Found outside the nucleus Bohr model – electrons are in specific energy levels Electron cloud model – electrons are in a random cloud

21. What is the structure of an atom? Bohr Model “Planetary Model” Schrödinger Model “Electron Cloud Model”

22. How are P, N, e - related? # protons = atomic number # electrons = # protons in a neutral atom # protons + # neutrons = atomic mass

23. What is a chemical symbol? Chemical symbol tells us what atom it is Always a CAPITAL LETTER, sometimes followed by a lower case letter Ex: Oxygen O Nitrogen N Sodium Na *Cobalt – Co *Carbon Monoxide – CO (Co is an element, CO is a compound)