IScience - Chapter 9 Test Flashcards
(26 cards)
Thomson’s experiments led to the discovery of the ___.
Electron
For an atom to be neutral, the number of protons must equal the number of ___.
Electrons
The idea of the atom was first proposed by ___.
Democritus
An element can be identified by the number of ___ in its nucleus.
Protons
The mass of an ___ is about equal to the mass of a proton.
Neutron
___ used the cathode ray experiments and determined that cathode rays are negatively charged.
Thomson
___ was invented in 1981 and allowed scientists to first see individual atoms.
Scanning tunneling microscope (STM)
The 3 basic components of an atom are ___.
Protons, neutrons, and electrons
The nucleus of an atom consists of ___.
Protons and neutrons
A single proton has what electrical charge?
Positive
What two particles would be attracted to each other?
Electrons and protons
In ___, the atomic number decreases by two.
Alpha decay
In ___, the atomic number increases by one.
Beta decay
A certain atom has 26 protons, 26 electrons, and 30 neutrons. Its atomic mass is ___.
56
The energy levels of an atom are occupied by ___.
Electrons
___ believed that all matter was made of fire, water, air, and earth.
Aristotle
___ discovered neutrons.
Chadwick
___ first called the building blocks of matter atomos.
Democritus
___ first introduced the concept that atoms combine in specific ratios.
Dalton
___ proposed a circular path for electrons.
Bohr
___ used the Gold Foil Experiment to observe alpha particles.
Rutherford
___ discovered electrons.
Thomson
___ is the name of the modern atomic model.
Electron cloud model
___ discovered radiation in uranium.
Curie
