UNIT 1: ST SCIENCE 10

- ATOMIC MODELS

- PERIODIC TABLE OF ELEMENTS

- REPRESENTING MODELS

*ATOMS AND ELEMENTS

*WHAT IS AN ATOM

*AN ATOM IS THE SMALLEST PARTICLE OF MATTER.

*IT CANNOT BE DIVIDED CHEMICALLY

*HOW SMALL IS AN ATOM?

- A SHEET OF PAPER IS ABOUT A MILLION ATOMS THICK

- A DROP OF WATER CAN CONTAIN MANY AS 10 SEXTILLION ATOMS.

(10000000000000000000000)

-THE DIAMETER OF THE PERIOD AT THE END OF THIS SENTENCE HAS 50 TRILLION ATOMS LINED UP IN A ROW IN IT

*ATOMIC MODELS

*DALTON’S MODEL 1808

SOLID BALLS. DIFFERENT COLORS. DIFFERENT MASSES

CARBON OXYGEN

- ALL ATOMS OF THE SAME ELEMENT ARE THE SAME

- ALL ATOMS OF ONE ELEMENT ARE DIFFERENT FROM THOSE OF OTHER ELEMENTS

- ELEMENTS CAN COMBINE

*ATOMIC MODELS

*THOMSON’S MODEL 1897

INCLUDED POSITIVE (PROTONS) AND NEGATIVE (ELECTRONS) CHARGES.

ZINC COPPER

- ADDED TO DALTON’S THEORY THAT ELEMENTS HAD BOTH POSITIVELY CHARGED AND NEGATIVELY CHARGED PARTS TO THEIR CORE

*ATOMIC MODEL

*RUTHERFORD’S MODEL 1911

FIRST TO INTRODUCE THE NUCLEUS, LIGHTWEIGHT WITH NEGATIVE CHARGED ELECTRONS SCATTERED RANDOMLY IN A LARGE SPACE OUTSIDE THE NUCLEUS.

BERYLIUM BERYLIUM

*ATOMIC MODELS

*RUTHERFORD-BOHR MODEL 1913

SMALL NUCLEUS(PROTONS AND NEUTRONS), MORE CONSISTENT ELECTRONS IN A SERIES OF ORBITS.

LITHIUM NICKEL

*PERIODIC TABLE OF ELEMENTS

*METALS, NONMETALS, AND METTALOIDS

*METALS

- IDENTIFIED BY THE STAIRCASE SHAPED LINE THAT CROSSES THE RIGHT HAND SIDE OF THE TABLE.

-METALS: GOOD CONDUCTORS OF ELECTRICITY AND HEAT. MALLEABLE AND DUCTILE SO THEY CAN BE EASILY SHAPED.

- SHINY

- ROOM TEMPERATURE THEY ARE SOLIDS (EXCEPT MERCURY)

- THEY REACT WITH ACIDS

*PERIODIC TABLE OF ELEMENTS

*METALS, NONMETALS, METALLOIDS

*NONMETALS

- POOR CONDUCTORS OF ELECTRICITY AND HEAT

-MOST ARE GASES AT ROOM TEMPERATURE

- SOLID NONMETALS CAN BE REDUCED TO POWDER

*PERIODIC TABLE OF ELEMENTS

*METALS, NONMETALS, METTALOIDS

*METTALOIDS

- (ALSO CALLED SEMI-METALS)

- SEVEN ELEMENTS WITH PROPERTIES OF BOTH METALS AND NONMETALS.

- SOME CONDUCT WELL, SOME DON’T. FOR THIS REASON THEY ARE SEMI-CONDUCTORS USED IN TRANSITORS, INTEGRATED CIRCUITS, AND LASERS

*PERIODIC TABLE OF ELEMENTS

*GROUPS

- THEY CORRESPOND TO THE COLUMN IN THE PERIODIC TABLE.

- EACH GROUP SHARE A SET OF SIMILAR CHEMICAL PROPERTIES BECAUSE THEY ALL HAVE THE SAME NUMBER OF VALANCE ELECTRONS.

- VALANCE ELECTRONS (THE NUMBER OF ELECTRONS IN THE OUTERMOST SHELL)

2 – 8 – 8 – 18 ETC

*PERIODIC TABLE OF ELEMENTS

*GROUPS

- ALAKALI METALS

ALL THE METALS OF THE 1ST GROUP. SOFT AND HIGHLY REACTIVE. IN PURE STATE, THEY MOST BE STORED IN OIL

- ALKALINE EARTH METALS

ALL THE METALS IN THE 2ND GROUP. HIGHLY MALLEABLE AND BURN EASILY IN THE PRESENCE OF HEAT.

-HALOGENS

NONMETALS IN GROUP 17. THEY REACT EASILY TO FORM COMPOUNDS (SALTS AND DISINFECTANTS)

-NOBLE GASES

RARE GASES OR INERT GASES. LAST COLUMN. VERY STABLE. THEY REACT MINIMALLY

*PERIODIC TABLE OF ELEMENTS

*PERIODS

CORRESPONDS TO THE ROW OF THE PERIDIC TABLE. ALL THE ELEMENTS HAVE THE SAME AMOUNT OF ELECTRON SHELLS

HAVE CORRESPONDING REPETITION IN THE PATTERNS OF THEIR PROPERTIES (P. 23)

MELTING POINT – TEMPERATURE OF SOLID TO LIQUID

BOILING POINT – TEMPERATURE OF LIQUID TO GAS

DENSITY – MASS PER UNIT OF VOLUME

ATOMIC RADIUS – DISTANCE FROM CENTER OF THE ATOM

FIRST IONIZATION ENERGY – ENERGY REQUIRED TO REMOVE OUTERMOST ELECTRON

ELECTRONEGATIVITY – ATTRACTING TO FORM BOND

*PERIODIC TABLE OF ELEMENTS

*ATOMIC NUMBER

REPRESENTS THE NUMBER OF PROTONS IN THE NUCLEUS OF AN ATOM

*ATOMIC MASS

REPRESENTS THE RELATIVE MASS OF THE ATOM AN ELEMENT BASED ON CARBON’S 6 PROTONS AND 6 NEUTRONS MEASURING 12u

*ISOTOPES

ADDED OR SUBTRACTED NEUTRONS DEPENDING ON THE ELEMENT

*REPRESENTING ATOMS

*LEWIS NOTATION (P. 27)

A SIMPLER REPRESENTATION OF THE ATOM, IN WHICH ONLY THE VALENCE ELECTRONS ARE ILLUSTRATED.

*REPRESENTING ATOMS

*RUTHERFORD-BOHR MODEL (P. 28)

ALL THREE FACTS MUST BE REPRESENTED:

1- THE PERIOD (REPRESENTING THE NUMBER OF ELECTRON SHELLS IN THE ATOM)

2- THE GROUP (REPRESENTING THE NUMBER OF VALENCE ELECTRONS)

3- ATOMIC NUMBER(REPRESENTING THE NUMBER OF PROTONS AND ELECTRONS)

*REPRESENTING ATOMS

*SIMPLIFIED ATOMIC MODEL (P. 28)

WE ROUND THE MASS TO THE NEAREST WHOLE NUMBER.

WE SUBTRACT MASS – ATOMIC NUMBER TO FIND HOW MANY NEUTRONS THERE ARE

EXAMPLE: CHLORINE 35.45u = 35

35 – 17 = 18 THEREFORE 17 PROTONS 17 ELECTRONS 18 NEUTRONS

*REPRESENTING ATOMS

*BALL AND STICK MODEL

BALLS WILL MAKE UP THE ELEMENTS

STICKS WILL MAKE UP THE BONDS