Introduction to Subatomic Particles and Atomic Models

These flashcards summarize key concepts about subatomic particles, atomic models, and notable experiments in atomic physics.

What did J.J. Thomson's cathode ray experiment reveal about atoms?

Atoms contain negatively charged particles, known as electrons.

What is the mass to charge ratio determined by Thomson's experiment?

Thomson could determine the mass to charge ratio of electrons but not the individual values of mass and charge.

What experiment did Robert Millikan and Harvey Fletcher perform?

They conducted the oil drop experiment to measure the charge of the electron.

What was Marie Curie's significant contribution to atomic physics?

She provided evidence for the existence of positively charged particles (alpha particles) and identified three types of radiation.

What are the three types of particles emitted by radioactive elements identified by Curie?

Alpha particles (positively charged), beta particles (negatively charged), and gamma rays (neutral).

In Rutherford's gold foil experiment, what unexpected result did he find?

Some alpha particles were reflected back, indicating the existence of a dense nucleus.

What is the Plum Pudding Model proposed by J.J. Thomson?

A model of the atom where electrons are embedded in a positively charged 'pudding'.

What does the atomic number of an element represent?

The atomic number is the number of protons in the nucleus of an atom.

What is the mass number of an atom?

The mass number is the total number of protons and neutrons in the nucleus.

What are isotopes?

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.