Atomic Theory Flashcards

Flashcards reviewing key concepts from the Atomic Theory lecture, including the contributions of early Greeks, Dalton, Thomson, Rutherford, Chadwick, and Bohr, as well as definitions of atomic number, mass, isotopes, and ions.

According to Aristotle, 'matter' had four possible properties: Moist, Dry, _, and Cold.

Hot

The early Greek elements that made up everything our senses could detect were fire, air, earth, and .

water

Medieval chemists developed the idea of _ that were subject to attractive and repulsive forces.

corpuscles

In 1808, based his model of the atom on solid experimental discoveries.

John Dalton

Dalton stated that elements are made up of extremely small particles called _.

atoms

Law of Definite Proportions states that a chemical compound always contains exactly the same proportion of elements by mass.

Dalton's

J.J. Thompson discovered and showed that atoms have negatively charged electrons and positively charged _.

protons

Thompson's model was called the _ model.

Plum Pudding

Rutherford proposed that the atom consists of a tiny, positively charged _, surrounded by a 'cloud' of negatively charged electrons.

nucleus

Rutherford's Gold Foil Experiment proved the existence of a small massive center to atoms, which would later be known as the _ of an atom.

nucleus

In 1932, James Chadwick discovered the _.

neutron

Bohr stated that electrons are restricted to a certain path called an _, a fixed distance from the nucleus.

orbital

Electrons could only emit or absorb when they move from one orbital to another.

energy

Electrons in the orbital farthest away from the nucleus are called _ electrons.

valance

The number of _ = Atomic number.

protons

The number of _ = Atomic Mass – Atomic number.

neutrons

The elements are differentiated from one another by the number of _ in the nucleus.

protons

The _ is the number of protons in the nucleus.

Atomic Number

If electrons are added to or subtracted from an atom, the resulting particle is called an _.

ION

Species having the same atomic number, but different atomic masses are called _.

Isotopes