1. Atomic Model

2. Atomic Model

3. Democritus 2000 years ago Could matter be divided???
Could not be divided forever-eventually you would reach a piece that was indivisible.
Atomos—means indivisible

4. Atomists Greek philosophers that agreed with Democritus
Atoms were small, hard particles that were constantly moving, could join together, and infinite in number

5. Dalton Early 1800’s Investigated gases
Discovered gases combine as if they were individual particles (atoms)

6. Dalton’s Model All elements are composed of atoms
Atoms are indivisible and indestructible
Atoms of an element are alike
Atoms of different elements are different
Compounds are formed by joining atoms of two or more elements

7. Thomson
1897
Electric current through a gas

8. Thomson’s Plum Pudding

9. Thomson Atom made of smaller particles Atom was known to be neutral.
Where did the negative come from??
He reasoned negative particles were contained in the positive material.

10. Rutherford
Early 1900’s

11. Rutherford

12. Rutherford Atom-small dense positively charged center
Negative charged electrons scattered outside nucleus
Space between electrons and positive center

13. Bohr
1913

14. Bohr Electrons move in definite orbits around center
Orbits, energy levels are certain distances away from nucleus

15. Modern Atomic Model

16. Whose Model?

17. Who Did What? Negative charged electrons outside nucleus
Electrons in orbits
Electrons in positive material—like “Plum-pudding”
Cannot be divided forever-atomos
Atoms of similar elements alike/different elements atoms different
Rutherford
Bohr
Thomson
Democritus
Dalton

18. Atomic Model—Name the Scientist
Across
1. electrons in definite orbits
5. compounds form by joining different atoms
Down
2. stated atom has small positive center
3. matter cannot be divided forever
4. discovered the electron

19. K Z Q F V G O R J H W V S A M R D U V I
Z W Y A O S E M B Y P B Y N M W Q K A Z
B C F J V I C E I M Y W W B Q R Q G L Y
A L U M R O F L A C I M E H C S G R E B
D V N A Y J L C Q B G E J I L X G N N J
M A R G A I D T O D N O R T C E L E C T
E N E R G Y L E V E L Z M F L Q V O E K
S V D Z L N Q G O R A R V Q Z N K X E P
D N O B L A C I M E H C X Y E F Y J L Q
S S A M C I M O T A W A M O T A N N E M
L I U V N F R E B M U N C I M O T A C D
D N O B T N E L A V O C D E M L I V T O
X G U H N Q C D Y X H X T C Y J D X R I
W W H T P C L B S B Y V X F Q O N F O R
I O N I C B O N D E L E M E N T A P N E
Z N H K N S U W I O N K L J X M U F S P
P O U Q G D V K O Q I D Z U I O W P O K
X B T L K C B G Z P J I A L R T F A J S
P P Z E P Q Y K V O U J Y G N L Y I N H
Q J T Y Q J S E W K T B R Y O I Q T J R
ATOM
ATOMIC MASS
ATOMIC NUMBER
CHEMICAL BOND
CHEMICAL FORMULA
COVALENT BOND
ELECTRON DOT DIAGRAM
ELEMENT
ENERGY LEVEL
FAMILY
GROUP