Atoms/Periodic Table Flashcards
(22 cards)
Atom
The smallest piece of matter that still retains the property of the element.
Nucleus
The positively charged center of an atom
Protons
Electrical charges with +1
Neutrons
No electrical charge
Electrons
Negative charges with -1
Quarks
The particles that make up neutrons and protons
Democritus
He stated that atoms make up all substances
John Dalton
An English scientist in the 1800’s
Joseph Thomson
He was an English physicist
Ernest Rutherford
He was another English physicist
Niels Bohr
He hypothesized that electrons travels in fixed orbits around the atom’s nucleus
Electron Cloud
The area around the nucleus of an atom where its electrons are likely found
Atomic Number
The number of protons in an atom is equal to the atomic number
Mass Number
The mass number of an atom is the sum of the number of protons and the number of neutrons in the nucleus of an atom
Isotopes
Atoms of the same element that have different numbers of neutrons
Average Atomic Mass
It is the weighted average mass of the mixture of its isotopes
Periodic Table
A table in which the elements are arranged by increasing atomic number and by changes in physical and chemical properties
Dmitri Mendeleev
He predicted the spaces of undiscovered elements on the table
Henry Mosely
He changed the arrangement of the periodic table based on their increasing atomic numbers instead of arrangement by atomic mass
Groups
The vertical columns in the periodic table
Electron Dot Diagram
it uses the symbol of the element and dots to represent the electrons in the outer energy level
Periods
The horizontal rows of elements on the periodic t
