1. Chemistry The study of matter, and how matter changes.

2. The Universe can be divided into two categories: 1. Matter: Anything having both mass & volume  Ex: your textbook, your bottle of water and the air surrounding you 2. Energy: the ability to exert a force across a distance  Ex: heat, light, electricity, motion 2

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5. Mass vs. Weight What is Mass?  The amount of matter (# of atoms or molecules) in an object What is Weight?  The effect of gravity on an object’s mass Since we are stuck here on Earth, we usually use mass & weight interchangeably. http://www.nyu.edu/pages/mathmol/textbook/weightvmass.html 5

6. Volume 6 What is Volume?  The amount of space an object occupies  Regular geometric shapes are easy to determine:  Cubic volume=L w h  Sphere = (4/3) pi r 3  Pyramid = (1/3) b h  Cylinder = pi r 2 h  Irregular Objects are harder:

7. Observing Matter  Qualitative Observations  Using Touch, Taste, Smell, Sight & Hearing  Finding words to describe an object  Quantitative Observations  Using measurements  Finding numbers to describe an object  The flower is:  White & yellow & sticky  4 cm tall stem  3.5 cm flower diameter 7

8. The Atom  All matter is composed of tiny particles called “atoms”  The Elements are the types of atoms we find in the universe  An atom is the smallest piece of an element which still looks and behaves like that element 8

9. The Atomic Model  What does an atom look like?  The answer to this question has evolved over many years… 9

10. Democritus 460 BCE – 370 BCE Ancient Greek philosopher who proposed that if an object was cut-in-half over and over again, eventually you reach a point at which it could not be cut-in-half anymore This piece was said to be indivisible or ( ἄ τομος ; “atomos”) 10

11. John Dalton 1803 - Matter divided into small, indivisible atoms - Each elements made of different atoms 11

12. Dalton’s Billiard Ball Model 12

13. JJ Thomson 1897 - discovered positive/negative charges within atom 13

14. JJ Thomson’s Raisin Bun Model 14

15. Ernest Rutherford 1911 -discovered negative electron cloud surrounding central, positively charged nucleus 15

16. Rutherford’s Beehive Model 16

17. Niels Bohr 1913 -described surrounding electrons to be locked into “orbits” of specific energy levels 17

18. Bohr’s Solar System Model 18

19. James Chadwick 1932 -discovers neutral neutron among positive nucleus -this explains mass discrepancy 19

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21. Quantum Mechanics 21 17 of the 29 attendees were, or became, Nobel Prize Winners

22. Quantum Mechanical Model Zones of highest probability of electron location Not required for this course!! 22