Flashcards in Lesson 3 Deck (31):
Elements are composed of tiny indivisible particles called Elements are composed of tiny indivisible particles called
States that mass in an isolated system is neither created nor destroyed
by chemical reactions or physical transformations.
LAW OF CONSERVATION OF MASS
According to this law, the total mass of the products must be equal to
the total mass of the reactants.
LAW OF CONSERVATION OF MASS
Proposed the Law of Definite Proportions
Joseph Louis Proust (1754-1826)
States that different samples of any pure compound contain the same
elements in the same proportions by mass.
LAW OF DEFINITE PROPORTIONS
States that if two elements combine to form more than one compound,
the ratio of the mass of an element to a fixed mass of the other element
is a whole number or a simple fraction.
LAW OF MULTIPLE PROPORTIONS
discovered the electron by
conducting a cathode ray experiment.
Joseph John Thomson (1856-1940)
discovered the proton and nucleus by
performing the gold foil experiment.
Ernest Rutherford (1871-1937)
discovered the neutron by bombarding a
beryllium atom with alpha particles producing an electrically neutral
particle have a mass slightly greater than that of a proton.
James Chadwick (1891-1974)
determined the charge of an
electron to be -1.60 x 10-19 coulomb using the oil-drop experiment.
Robert Andrews Millikan (1868-1953)
They are atoms with the same atomic number but different mass
Indicates the number of atoms of a given isotope from the total number
of atoms of all isotopes of that element.
is the average mass of all of the naturally-occurring
isotopes of an element.
The horizontal rows of the table are called
• Elements with similar chemical and physical properties lie in vertical
groups or families.
solids, can conduct electricity, and are usually ductile ,
malleable, and can form alloys.
have a wide variety of properties
Alkaline Earth Metals
Two rows at the bottom
Lathanides and Actinides
Some nonmetals can often exist in several different and distinct forms,
called_____each having its own properties.
is the smallest identifiable unit into which some pure
substances like sugar and water can be divided and still retain the
composition and chemical properties of the substance.
are described on paper by
representing the composition of each element and compound
participating by a symbol or formula.
indicates the composition of the compound
indicates how certain atoms are grouped together
indicates an even higher level of structural detail,
showing how all of the atoms are attached within a molecule.
consist of ions, atoms or groups of atoms that bear a
positive or negative electric charge.
Three types of ions
Monatomic Cations -loses an electron
Monatomic Anions-gains an electron
Polyatomic Ions - two or more atoms