Review of Lecture Notes on Atomic Theory and Calculations

These flashcards cover key concepts from the lecture on atomic theory, calculations, significant experiments, and the structure of atoms.

What does the law of definite proportions state?

In a pure compound, elements always combine in a fixed ratio by mass.

Who proposed the atomic theory that all matter is composed of tiny individual particles called atoms?

John Dalton.

What significant experiment did JJ Thomson conduct?

The cathode ray tube experiment, which demonstrated that electrons are negatively charged particles.

What did Millikan's oil drop experiment determine?

The charge of an electron, which is approximately 1.6 \times 10^{-19} Coulombs.

What was the result of Rutherford's gold foil experiment?

It concluded that the atom has a concentrated positive charge located in a small nucleus.

What is the atomic number (Z)?

The total number of protons in an atom's nucleus.

How are isotopes defined?

Atoms of the same element that have the same number of protons but different numbers of neutrons.

What role do neutrons play in the nucleus?

Neutrons help stabilize the nucleus by balancing the positive charges of protons and preventing electromagnetic repulsion.

Who created the periodic table after dreaming of a systematic arrangement of elements?

Dmitri Mendeleev.

How did Mendeleev account for undiscovered elements in his periodic table?

He left gaps and correctly predicted the properties of elements that had not yet been discovered.

What is the Law of Multiple Proportions?

A law stating that elements may form multiple compounds with fixed atomic ratios.

What did Avogadro's Hypothesis contribute to atomic theory?

It explained the existence of diatomic molecules and helped clarify gas behavior in chemical reactions.

What is the difference in scale between an atomic radius and a nuclear radius?

The atomic radius is about 1 nanometer, while the nuclear radius is much smaller at approximately 5 \times 10^{-15} meters.

What force holds protons and neutrons together in the nucleus?

The strong nuclear force.

In atomic notation, what does the mass number (A) represent?

The total sum of protons and neutrons in the nucleus of an atom.