WHAT%ARE%THE$ATOMS?%DEMOCRITUS’$ATOMIC$THEORY$$

!  All$ma3er$consists$of$ATOMS$

!  Atoms$are$indestruc?ble$

!  Atoms$are$solid$and$invisible$

!  Atoms$are$homogeneous$

!  Atoms$differ$in$size,$shape,$

mass,$posi?on,$arrangement$DEMOCRITUS$460$BC$–$370$BC$

Greek$Philosopher$

ATOM%=%CAN%NOT%BE%DIVIDED%

PARTICLE(S)$$=$$ATOM(S)$Imagine%atoms%like%<ny%balls%or%circles%

WHAT%ARE%THE$ELEMENTS?%!  A%substance%made%up%of%just%ONE$KIND$OF$ATOMS.%!  Cannot%be%broken%down%into%simple%substances%by%a%physical%or%

chemical%process.%

!  ELEMENTS$have$the$same$atomic$number.%!  118%elements%are%known%(%94%found%naturally%+%24%made%in%laboratory)%

!  Are%represented%by%symbols.%

!  A$GROUP$OF$ATOMS$joined$together$is$called$a$MOLECULE$

Helium$ Hydrogen$ Oxygen$

A$CHEMICAL%SYMBOL$FOR$EACH$ELEMENT!%

Sodium$ Element’s%%Name%

Element’s%%Symbol%

11$ Atomic%Number%

Na$%–{%from%La(n%‘natrium’%}%

ROWS%ARE%CALLED%–{%PERIODS$COLUMNS%ARE%CALLED%–{%GROUPS$

METALS%=%%LEFT$SIDE$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$NON%METALS%=%%RIGHT$SIDE$

Sodium$ Name%

Symbol%

11$ Atomic%Number%

7th%SCIENCE%%%%%%TEACHER:%IRINA%RUIZ%FIGUEROA%%

STUDENT:%%……….…………………………….………%

Atomic$Number$ $Element’s$Symbol$ Element’s$Name$

Use%the%back%of%this%page%to%design%your%element’s%list%from%1%to%20.%

ELEMENTS%ON%EARTH%

Ques<ons%for%Homework%

1.  What%are%the%atoms?%

2.  How%many%elements%are%found%in%nature?%

3.  Which%is%the%most$common$metal$found%in%Earth%crust?%4.  Which%is%the%most%common%non_metal$found%in%the%Earth%crust?%5.  Suggest%why%people%used%to%believe%that%water%was%an%element?%

6.  Name%2%gases%that%are%found%in%air.%%

7.  Is%AIR%an%element?%Explain%your%answer.%

8.  Which%element%has%atoms%with%the%smallest%mass?%

9.  Which%of%the%first%20%elements%has%atoms%with%the$greatest$mass?%

10.  Give%the$names%(not%symbols)%of%two$elements$in%the%same%period%as%magnesium.%

11.  %Give%the$symbols%(not%names)%of%two$elements$in%the%same%group%as%helium.$