THE NATURE OF MATTER

SECTION 2-1

TURN TO PAGE 34 IN YOUR BOOK AND WE WILL READ THE CAPTION UNDER THE PICTURE ON THAT PAGE.

BIOCHEMISTRY: THE STUDY OF THE CHEMICALS OF LIVING THINGS AND THE CHANGES THAT THOSE CHEMICALS UNDERGO—THE CHEMISTRY OF LIFE!

LIFE DEPENDS ON CHEMISTRY—FOODS YOU EAT AND OXYGEN YOU INHALE ARE USED BY YOUR BODY IN CHEMICAL REACTIONS TO KEEP YOU ALIVE.

ATOM—THE BASIC UNIT OF LIFE,

ATOMS ARE INCREDIBLY SMALL. HOWEVER THEY CONTAIN SUBATOMIC PARTICLES.

THE SUBATOMIC PARTICLES ARE PROTONS, NEUTRONS, AND ELECTRONS. PG. 35 PLEASE.

Neutron, and electrons.

PROTONS HAVE A POSITIVE CHARGE AND NEUTRONS ARE NEUTRAL (NO CHARGE). THEY ARE FOUND IN THE CENTER OF THE ATOM (THE NUCLEUS)

THE ELECTRON IS NEGATIVELY CHARGED AND THEY ARE IN CONSTANT MOTION AROUND THE NUCLEUS. ATOMS ARE NEUTRAL (NO CHARGE ON THE ENTIRE ATOM).

MOTION AROUND THE NUCLEUS OF THE ATOM.

CHEMICAL ELEMENT—A PURE SUBSTANCE THAT CONSISTS ENTIRELY OF ONE TYPE OF ATOM.

MORE THAN 100 ARE KNOWN TO MAN.

THE PERIODIC TABLE SHOWS THE ELEMENTS.

GO TO APPENDIX G PLEASE.

ISOTOPES

AN ISOTOPE IS AN ELMENT (ATOM) WITH DIFFERENT NUMBERS OF NEUTRONS.

LETS LOOK AT CARBON AS AN EXAMPLE.

THERE IS CARBON-12, CARBON-13, CARBIB-14 PAGE 36 PLEASE.

BECAUSE THEY HAVE THE SAME NUMBER OF ELECTRONS, ALL ISOTOPES OF AN ELEMENT HAVE THE SAME CHEMICAL PROPERTIES.

SOME ISOTOPES ARE RADIOACTIVE—THE GIVE OFF RADIOACTIVE PARTICLES AND CAN BE DANGEROUS.

HOWEVER THEY CAN BE USEFUL TO TREAT CANCER, KILL BACTERIA, AND FIND THE AGE OF FOSSILS.

CHEMICAL COMPOUNDS

COMPOUND—A SUBSTANCE FORMED BY THE CHEMICAL COMBINATION OF TWO OR MORE ELEMENTS.

WATER AND COMMON SALT ARE COMPOUNDS,

NaCl is salt and H2O is water.

THE ATOMS ARE HELD TOGETHER BY CHEMICAL BONDS (FORCES)

CHEMICAL BONDS

CHEMICAL BONDS (FORCES) HOLD ATOMS TOGETHER TO MAKE COMPOUNDS.

IONIC BONDS - THESE BONDS ARE FORMED WHEN ONE OR MORE ELECTRONS ARE TRANSFERRED FROM ONE ATOM TO ANOTHER.

PAGE 38 PLEASE

COVALENT BONDS– THIS BOND FORMS WHEN ELECTRONS ARE SHARED BETWEEN ATOMS.

THE COMPOUND FORMED IS CALLED A MOLECULE.

WATER IS AN EXAMPLE

PAGE 38 PLEASE.

THE MOLECULE IS THE SMALLEST UNIT OF MOST COMPOUNDS.

SOME MOLELCULES ARE ATTRACTED TO OTHER MOLECULES BECAUSE OF THE STREGENTH OF THE ATOMS IN THE MOLECULE.

THIS IS CALLED van der Waals FORCES.

SEE PAGE 39.