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The ................ that all matter is composed of atoms grew out of many ‏ observations and laws

Law of Conservation of Mass is

is positively charged.

are atoms of one element that have the same number of protons (atomic number) and different number of neutrons.

When two elements A and B combine with each other form two or more compounds ratios masses elements simple whole numbers

Cathode Ray Tube Experiment is

The number of protons in the nucleus of an atom is called the

located in an atom’s nucleus determines the element’s identity.

Law of Multiple Proportions is

The...........has essentially the entire mass of the atom.

Plum-Pudding Model of The Atom is

Explains the positive (+), negative (-) charged behavior of matter

The atom contains a tiny, dense center called the

Gold Foil Experiment is

Discovered the atom’s nucleus (protons) & disapproved the plum-pudding model.

differ in mass number because they have different number of neutrons.

Oil Drop Experiment is

Law of Definite Proportions is

was an English physicist who was awarded the 1935 Nobel Prize in Physics

are chemically identical, but may be physically different.

The atom is composed of a positive cloud of matter in which electrons are embedded.

Led to determining the electrical charge of the electron.

The theory that all matter is composed of atoms grew out of many

A given chemical compound always contains the same elements in the exact same proportions (by mass)

When The Number of Neutrons Varies

Discovered the electron and determined the electron’s charge- to-mass ratio.

is referred to as “Z”, it’s considered as the “fingerprint” of any element.

The three most important laws that led to the development and acceptance of the atomic theory are:

➢ Matter is neither created nor destroyed in a chemical reaction.

Is discovery of the neutrons, neutral particles within the nucleus of the atom.