ATOMS,MOLECULES AND IONS.

Question 1

STATE DALTON’S ATOMIC THEORY.

Answer 1

1. EACH ELEMENT IS UP OF TINY PARTICLES CALLED ATOMS.
2. THE ATOMS OF A GIVEN ELEMENT ARE IDENTICAL;THE ATOMS OF DIFFERENT ELEMENTS ARE DIFFERENT IN SOME FUNDAMENTAL WAYS.
3. CHEMICAL COMPOUND ARE FORMED WHEN ATOMS OF DIFFERENT ELEMENTS COMBINE WITH EACH OTHER. A GIVEN COMPOUND ALWAYS HAS THE SAME RELATIVE NUMBERS AND TYPES OF ATOMS.
4. CHEMICAL REACTION INVOLVES THE REORGANIZATION OF ATOMS IN THE WAY THEY BOND TOGETHER. NO ATOMS ARE CREATED OR DESTROYED IN A CHEMICAL REACTION.

Question 2

STATE THE LAW OF DEFINITE PROPORTIONS OR LAW OF CONSTANT COMPOSITION.

Answer 2

ALL SAMPLE OF A PURE COMPOUND CONTAINS THE SAME ELEMENTS IN THE SAME PROPORTION BY MASS.

-JOSEPH PROUST

Question 3

STATE THE LAW OF MULTIPLE PROPORTION.

Answer 3

WHEN TWO ELEMENTS REACT TO FORM MORE THAN ONE COMPOUND, A FIXED MASS OF ONE ELEMENT WILL REACT WITH MASS OF THE OTHER ELEMENT IN A RATIO OD SMALL,WHOLE NUMBERS

Question 4

DESCRIBE J.J THOMPSON CATHODE RAY EXPERIMENT.

Answer 4

• HE INVESTIGATED THE ELECTRICAL DISCHARGES THAT COULD BE PRODUCED IN PRESSURE GASES.
• USING A CRT,WHEN HIGH VOLTAGE WAS APPLIED ACROSS THW ELECTRODES, A VISIBLE BEAM CALLED CR APPEARED BETWEEN THE 2 METAL ELECTRODES.
• THE CR WAS WAS DEFLECTED TOWARD THE POSTIVE CHARGE,DEFLECTED BY APPLIED MAGNETIC FIELD, PRODUCED SAME WAY WITH DIFFERENT ELECTRODE METALS.

CONCLUSIONS:
PARTICLES ARE NEG CHARGED.
PARTICLES ARE LESS MASSIVE THAN ATOMS AND ARE FUNDAMENTAL SUBATOMIC PARTS OF ALL ATOMS

Question 5

DESCRIBE A.MILIKAN OIL DROP EXPERIMENT.

Answer 5

• HE CREATED MICROSCOPIC OIL DROPLETS, WHICH COULD BE ELECTRICAL CHARGED BY FRICTION OR USING X RAYS
• TGW OIL DROPLETS INTIALLY FELL DUE TO GRAVITY, BUT THEIR DOWNWARD MOTION COULD BE SLOWED OR REVERSED BY AN ELECTRIC FIELD LOWER IN THE APPARATUS.
• BY ADJUSTING ELECTRIC FIELD STRENGTH HE CAREFULLY CALCULATED CHARGE ON INDIVIDUAL DROPLET AND ALSO FOUND MASS OF THE ELCTRON.

Question 6

DESCRIBE ERNEST RUTHERFORD EXPERIMENT.

Answer 6

• PERFORMED EXP USING A BEAM OF HIGH SPEED ,POSTIVELY CHARGED ALPHA PARTICLES PRODUCED BY RADIOACTIVE DECAY OF RADIUM
• AIMED A BRAN OF ALPHA PARTICLES, SOURCE EMBEDDED IN A LEAD BLOCK TO ABSORB MOST OF THE RADIATION, AT A THIN PIECE OF GOLD FOIL.
• HE EXAMINED THE SCATTERING OF ALPHA PARTICLES USING A LUMINESCENT SCREEN THAT GLOWED BRIEFLY WHEREBHIT BY AN ALPHA PARTICLE.

CONCLUSION:

• VOLUME OF ATOM IS LARGE ,EMPTY SPACE.
• A SMALL, RELATIVELY HEAVY, POSITIVELY CHARGED BODY MUST BE AT THE CENTER OF AN ATOM.

Question 7

WHAT IS ATOMIC MASS UNITS.

Answer 7

1amu=1/12 ×MASS OF CARBON-12 ATOM

1 amu=1.6605×10^-24g.

The DALTON (Da) or Unified atomic mass unit (u) are equalvalent alternatives.

Question 8

WHAT IS FUNDAMENTAL UNIT OF CHARGE (ELEMENTARY CHARGE)

Answer 8

EQUALS MAGNITUDE OF AN ELECTRON

THAT IS 1.603×10^19 C

Question 9

WHAT IS THE PERIODIC LAW?

Answer 9

TGE PROPERTIES OF ELEMENTS ARE PERIODIC FUNCTIONS OF THE ATOMIC NUMBERS .

SOME ADD INFO:

PERIODIC TABLE ARRANGES ELEMENTS INORDER OF INCREASING ATOMIC NUMBERS.

GROUPS ATOMS WITH SIMILAR PROPERTIES IN SAME VERTICAL COLUMNS.(GROUPS)

Question 10

HOW DO YOU NAME COMPOUNDS CONTAINING ONLY MONO ATOMIC IONS?

Answer 10

1.A BINARY COMPOUND CONTAINING MONO ATOMIC IONS ,

NAME CATION FIRST, I.E NAME OF METAL.

2.NAME ANION SECOND I.E NON METAL AND REPLACE ENDING WITH SUFFIX -IDE.

NaCl–sodium chloride.

Question 11

HOW DO YOU NAME COMPOUNDA CONTAINING POLYATOMIC IONS?

Answer 11

1 NAME CATION
2.NAME ANION .

NH4CL—AMMUNIUM CHLORIDE.
CaSO4–CALCUIM SULFATE.
AL2(CO3)3–ALUMINUM CARBONATE.

Question 12

HOW DO YOU NAME COMPOUNDS CONTAINING A METAL ION WITH VARIABLE CHARGE?

Answer 12

MOST TRANSITION METALS AND SOME MAIN GROUND METALS CAN FORM 2 OR MORE CATIONS WITH DIFF CHARGES.

1. NAME CATION AND SPECIFY CHARGE BY ROMAL NUMERIAL IN PARENTHESES
2. NAME ANION
3. CHANGE ENDING WITH IDE SUFFIX

Snf2—Tin (ll) fluoride.
FeCl2–iron(ll)chloride.

Question 13

HOW DO YOU NAME IONIC HYDRATES?

Answer 13

IONIC HYDRATES ARE IONIX COMPOUNDS THAT CONTAIN WATER MOLECULES AS AN INTERGRAL COMPONENT OF THEIR CRYSTALS.

• FORMULAS IS WRITTEN BY APPENDING A VERTICALLY CENTERED DOT.
• A COEFFICIENT REPRESENTING THE NUMBER OF WATER MOLECULES.

FINALLY THE FORMULA FOR WATER.

COPPER (ll) SULPHATE PENTAHYDRATE.

CuSO4 . 5H2O

SODIUM CARBONATE DECAHYDRATE Na2CO3.10H2O

Question 14

HOW DO YOU NAME MOLECULAR COMPOUND COMPOSED OF 2 ELEMENTS.

Answer 14

THE MORE METALLIC ELEMENT IS FIRST (ONE FURTHER TO THE LEFT OR DOWN OF PERIODIC TABLE)

THE NON METALIC IS NEXT.
CHANGE ITS ENDING WITH SUFFIX-IDE

NUMBERS OF ATOMS ARE DESIGNATED BY THE GREEK PREFIXES.

NOTE:
WHEN 2 VOWELS ARE ADJACENT,THE a IN THE GREEK PREFIX IS DROPPED. (USUALLY).

SO2–SULFUE DIOXIDE.
N2O5–DINITROGEN PENTOXIDE
PF6–PHOSPHORUS PENTAFLOURIDE
N204–DI NITROGEN TETROXIDE.

Question 15

HOW DO YOU NAME BINARY ACIDS?

Answer 15

IF A COMPOUND IS A BINARY ACID,ITS COMPOSED OF HYDROGEN AND ONE OTHER NON METALIC ELEMENT.

1. THE WORLD HYDROGEN IS CHANGED TO HYDRO.
2. THE OTHER NON METALIC ELEMENT IS MODIFIED BY ADDING SUFFIX-IC.

3.THE WORD ACID IS ADDED AS A SECOND WORD.
HF–HYDRO FLOURIC ACID.
H2S–HYDRO SULFURIC ACID.

Question 16

HOW DO YOU NAME OXYACIDS?

Answer 16

COMPOUNDS CONTAINING HYDROGEN, OXYGEN AND ATLEAST ONE OTHER ELEMENT AND ARE BONDED IN SUCH A WAY AS TO IMPART ACIDIC PROPERTIES IS AN OXYACID.

TYPICAL OXYACID ,CONSIST OF HYDROGEN COMBINED WITH A POLYATOMIC OXYGEN CONTAINING ION.

NAMED AS FOLLOWS;
1.OMIT HYDROGEN.

2. START WITH THE ROOT NAME OF THE ANION.
3. REPLACE -ATE WITH -IC OR -ITE WITH -OUS
4. ASD ACID.

HC2H3O–ACETIC ACID
HNO3–NITIC ACID
H2SO4–SULFURIC ACID
HESO3–SULFUROUS ACID.