Studied by 2 people
plum pudding model
the atomic model developed by J. J. Thomson that views atoms as spheres of positively charged material with embedded electrons
Democritus' thoughts
atoms are indivisible particles shape and texture varies on the type of matter
aristotle thought
matter is continuous, not made of discrete particles can be subdivided an unlimited number of times
John Dalton thought
elements are made of atoms atoms are indivisible, cannot be destroyed atoms of an element are all alike combine chemically in small whole number ratios
law of electrostatic charges
states that opposite electrical charges attract each other, while like charges repel each other
JJ Thompson thought
tiny, negatively-charged particles, electrons electrons are part of the atom so atoms are divisible
Rutherford thought
atom's mass and positive charge are packed into a small space called the nucleus
nuclear model
an atom is made up of a tiny, dense, positively charged central nucleus surrounded by negatively charged electrons
Modern Atomic Model
quantum mechanics explore the behavior of matter and energy at the atomic and subatomic levels
Robert Boyle
Began the transition from alchemy to chemistry
Antoine Lavoisier
Made one of the first lists of known elements, which included 33 elements known in his day and explained that fire is not an element
Jacob Berzelius
Developed a system of symbols for naming the elements, using 1–2 letters of each element’s Latin name
Johann Döbereiner
Created triads and discovered periodicity.
John Newlands
Arranged elements in order by atomic mass and developed the law of octaves
Dmitri Mendeleev
Arranged elements in columns by increasing atomic masses
Henry Moseley
Discovered a way to determine the atomic number
Bohr thought
when at high temperatures each element produces an emission spectrum that produced oly certain wavelengths of light
Bohr model
electrons travel in distinct spherical regions called energy levels at fixed distances from the nucleus
quantum-mechanical model
the currently accepted atomic model in which electrons are found in orbitals that are positioned around a nucleus that contains protons and (usually) neutrons
energy level
in the Bohr model of the atom, the regions located at fixed distances from the nucleus of an atom in which electrons are found
quantum mechanics
the branch of physics that explores the behavior of matter and energy at the atomic and subatomic level
alpha particle
a helium nucleus that is emitted from a nucleus when a radioactive isotope experiences alpha decay
nucleus
the dense, central portion of an atom
photon
a wave bundle, or particle, of electromagnetic energy
orbital
the region within an atom where an electron will most probably be located; part of the quantum-mechanical model of an atom
workability
the basis upon which a model is assessed, taking into account how well it explains or describes a set of observations and how well the model makes predictions
periodic table
a table that organizes essential information about elements in a manageable format
element
a pure substance that consists of only one kind of atom
triad
a group of three elements with similar characteristics that demonstrates periodicity
periodicity
a repeating pattern in a characteristicla
law of octaves
early form of the periodic law devised by John Newlands as he noticed that every eighth known element had similar properties when ordered by increasing atomic mass
periodic law
states that the properties of elements vary periodically with their atomic numberst
transuranium elements
an element with an atomic number greater than 92, the atomic number of uraniumg
group
a column of the periodic table that includes elements that have similar properties because they have similar electron configurations; also called a family
period
a row in the periodic table that includes elements that have their valence electrons in the same energy level. The period number represents the valence shell; also known as a series
metal
one of a general group of elements with similar characteristics, such as being solid at room temperature, lustrous, malleable, ductile, and a good conductor of heat and electricity
nonmetal
one of a general group of elements with similar characteristics, such as generally being a gas or a soft, crumbly solid at room temperature, and being a poor conductor of heat and electricity
metalloid
one of a general group of elements with characteristics that are between those of metals and nonmetals; also know as a semiconductor
atomic radius
the distance from the center of an atom's nucleus to its outermost electron
ionization energy
the amount of energy required to remove an electron from an atomf
first ionization energy
the minimum energy required to remove the first electron from its outermost shell
electron affinity
the change in energy when an electron is added to a neutral atom to from an anion (the opposite of ionization energy)
electronegativity
the measure of the attraction between the nucleus and the shared valence electronsd
descriptive chemistry
the study of elements and the compounds they form
alkali metals
element in group 1 on the periodic table; a soft, highly reactive metal that has one valence electron that it easily loses to form a 1+ cation
transition metal
an element from the d block of the periodic table (groups 3-12); a metal that typically has one or two valence electrons that it easily loses to form a 1+ or 2+ cation
alkaline-earth metal
an element of group 2 on the periodic table; a reactive metal, having tow valence electrons that it easily loses to form a 2+ cation
inner transition metal
an element from the f block of the periodic table (lanthanoid and actinoid series)
actanoid series
a set of elements typically placed at the bottom of the periodic table that consists of the f-block elements form period 7l
lanthanoid series
A set of elements typically placed at the bottom of the periodic table that consists of the f-block elements from period 6
oxide
a compound that contains oxygen, oxygen combined with one other element
sulfide
a compound that contains sulfur, often combined with another element
halogen
an element of group 17 on the periodic table; highly reactive nonmetal with seven valence electrons
noble gas
an element of group 18 on the periodic table; nonreactive (inert) nonmetallic gas with a full valence shell
continuous theory of matter
the theory that matter can be continuously subdivided without end
atomism
the theory that matter was made of separate, discrete particles that cannot be divided infinitely without losing its properties
atom
the smallest particle that makes up an element and is capable of chemical interactionsl
law of definite proportions
states that every compound is formed of elements combined in specific ratios by mass that are unique for that compound
law of multiple proportions
states that whenever a fixed amount of one element can combine with different masses of a second element, the ratio of masses can be reduced to small, whole numbers
electron
a subatomic particle that has a negative charge and very little massal
alpha particle
a particle consisting of two protons and two neutrons; a positively charged ion
nucleus
the extremely small and dense center of an atom
proton
a subatomic particle located in the nucleus of every atom; has a positive charge
atomic number
the number of protons in the nucleus of an atom
neutron
a subatomic particle located in the nucleus of most atoms; has no charge and a mass of approximately 1 u isotope
mass number
the sum of the protons and neutrons in the nucleus of an atom i
isotope notation
a special notation, used to identify important information about an isotope, consisting of a chemical symbol, atomic number, and mass number
unidentified atomic
the unit used to measure the mass of an atom; also known as a dalton (Da)
atomic mass
the weighted average (an average that gives more importance to certain values than to others) of the masses of the element's isotopes
ion
a charged atom or group of atoms that has gained or lost electrons, producing an unequal number of protons and electrons
anion
a negatively charged ion
cation
a positively charged ion
Note
Flashcard