Atoms and the Periodic Table Flashcards
(22 cards)
The smallest piece of matter that still retains the property of the element.
Atoms
Protons and Neutrons are found in a small, positively charged center of a atom.
Nucleus
Particles with an electrical charge.
Protons
Neutral particle that do not have an electrical charge.
Neutrons
Particles with an electrical charge.
Electrons
Protons and neutrons, however, are made up of smaller particles.
Quarks
Proposed the idea that atoms make up all substances.
Democritus
Modernization of Aristotle’s idea of the atoms provided a physical explanation for chemical reaction.
John Dalton
Experiments that atoms contain small, negatively charged particles.
Joseph Thomson
Proposed that all the masses of atoms are positively charged.
Ernest Rutherford
Hypothesized that electrons traveled in fixed orbits around the atom’s nucleus.
Niels Bohr
The area around the nucleus of an atom where its electron are most likely found.
Electron cloud
The number of protons in an atom is equal to a number.
Atomic number
The sum of the number of protons and the number of neutrons in the nucleus of an atom.
Mass numbers
Atoms of the same element that have different numbers of neutrons.
Isotopes
The weighted-average mass of an element of its isotopes.
Average Atomic Mass
The elements are arranged by increasing atomic number and by change in physical and chemical properties.
Periodic Table
Created the arrangement of elements.
Dmitri Mendeleev
Led the arrangement of elements based on their increasing atomic numbers instead of atomic mass.
Henry Moseley
The vertical columns in the Periodic table.
Groups
Uses the symbol of the element and dots to represent the electrons in the outer energy level.
Electrons dot diagrams
The horizontal rows of elements on a Periodic table.
Periods
