Atomic Model

Atomic Model

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

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

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

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

Thomson 1897 Electric current through a gas

Thomson’s Plum Pudding

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.

Rutherford Early 1900’s

Rutherford

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

Bohr 1913

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

Modern Atomic Model

Whose Model?

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

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

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