Atoms and Isotopes

What were the three laws of matter that were created during the scientific revolution?

Law of conservation of Mass, Law of Definite Proportion, Law of multiple proportions

Who determined the law of conservation of mass?

Antoine Lavoisier (1743-1794)

Who determined the law of definite proportions?

Joseph Proust (1754-1826)

Who determined the law of multiple proportions?

John Dalton (1766-1844)

What are molecules?

2_ atoms attached to each other by bonds

What was Dalton’s Atomic Theory based on?

matter having ultimate and indivisible particles

What was the significance of Dalton’s atomic theory?

unified law of conservation of mass, law of definite proportions, law of multiple proportions

What was part one of Dalton’s Atomic Theory?

Each element is composed of tiny, indestructible particles called atoms

What was part two of Dalton’s Atomic Theory?

All atoms of the same element have the same mass

What was part three of Dalton’s Atomic Theory?

Atoms combine in whole number ratios

What was part four of Dalton’s Atomic Theory?

Matter cannot be created or destroyed

What two things must happen for something to be neutral?

No overall charge or net neutral charge

Who was Karl Ferdinand Braun?

1850-1918: German inventor an dphysicist, nobel prize in physics, etc etc

What is a cathode ray?

Stream of electrons

Who was JJ Thomson?

English scientist

What was JJ Thomson’s hypothesis?

The cathode ray was composed of tiny, negatively charged particles

What was JJ Thomson’s experiment?

Measured the force it took to deflect a cathode ray off its path and therefore measured the charge & mass of the particles

Who discovered the cathode ray tube?

Karl Ferdinand Braun (1850-1918)

What was JJ Thomson’s hypothesis about the cathode experiment?

Light is not deflected by an electric field, charged matter is attracted to electric field

What were the results of JJ Thomson’s cathode ray experiment?

Cathode ray was composed of small, negatively charged particles

Millikan’s Oil Drop Experiment

Shot droplets of oil through a container with an upper positive field and a lower negative field and measured the charges on the differently-sized droplets

What are beta particles?

electrons

What are alpha particles?

nucleus w 2 protons and 2 neutrons (helium)

What are gamma rays?

high energy rays

When does alpha radiation occur?

When there is an unequal amount of protons and neutrons in the nucleus it emits an alpha particle.

What “scale” is amu (atomic mass unit)

A relative scale of mass