Studied by 21 people
chemistry
the study of the composition, structure, and properties of matter, the process that matter undergoes, and the energy changes that accompany these processes.
chemical
a compound or substance that has been purified or prepared
mass
the measure of the amount of matter in an object
matter
anything that has mass and takes up space
atom
smallest unit of an element that maintains the chemical identity of that element
molecule
smallest unit of a compound that retains the same properties of a compound
element
a pure substance that cannot be broken down into simpler, stable substances
compound
a pure substance that can be broken down into simple substances, made of more than one element
extensive property
depends on the amount of matter that is present. ex. volume, mass, or amount of energy in a substance
intensive property
does not depend on the amount of matter present. ex. boiling, melting, density, or the ability to conduct heat or electricity
physical properties
something we can observe and measure without changing the identity of the substance. ex. finding melting or boiling point, density
chemical properties
substance’s ability to undergo changes that transform it into different substances. ex. flammability, toxicity, acidity, reactivity
change of state
the change of a substance from one physical state to another
plasma
high-temperature physical state where atoms lose most of their electrons
mixture
a blend of two or more kinds of matter, each of which retains its own identity and properties
physical change
a change in a substance that does not involve a change in the identity of the substance. ex. grinding, cutting, melting, boiling
chemical change
a change in which one or more substances are converted into different substances. clues to this are color change, precipitation, and gas. ex. burn, corrode, rust, explode
AMU
atomic mass unit
conservation of mass
mass cannot be created or destroyed
Law of Definite Proportions
chemical compound always has fixed ratio by mass
Law of Multiple Proportions
when 2 elements combine, their ratio is in whole numbers
mole
6.02 x 10^ 23. unit for very small things in very large numbers
molar mass
mass of one mol of a substance, ex. 6 g/mol
isotope
atoms with the same number of protons but different numbers of neutrons
empirical formula
most basic ratio of elements in a compound
molecular formula
true ration of elements in a compound, unsimplified
ion
an atom in which # of electrons is not equal to the # of protons
anion
negatively charged ion
cation
positively charged ion
isoelectric
same charge
Democritus
Proposed that the world is made of tiny particles. Was the first person to come up with the idea of an atom
Aristotle
Believed matter was made up of five elements
John Dalton
English scientist who developed an atomic theory with five main postulates. Also the first to discover the properties of an atom
JJ Thomson
English scientist who discovered the electron using a cathode-ray tube, “Plum Pudding” Model
Robert A. Milikan
Determined the charge of an electron using the oil drop experiment
Ernest Rutherford
Discovered protons and the nucleus of an atom using the gold foil experiment. Also discovered that atoms are mostly empty space
Niels Bohr
His atomic model shows electrons in distinct energy levels, electron configuration
James Chadwick
Discovered the neutron, led to the atomic bomb
Frederick Soddy
Discovered the isotopes of elements
Henry Moseley
Linked the atomic number to the number of protons in the nucleus and that protons have a positive charge
Antoine Lavoisier
Father of modern chemistry, made it more quantitative as opposed to qualitative
Robert Bunsen
Invented the Bunsen burner, techniques in data collection with compounds and elements
Bohr Diagram
circular diagram showing electrons
Aufbau Principle
fill in lowest available energy level first
Pauli Exclusion Principle
Each orbital can hold a max of 2 electrons
Electrons must spin in opposite directions
Arrows represent electrons
Hund’s Rule
Spread out electrons within an energy sublevel before pairing them up
6 branches of chemistry
organic, inorganic, physical, analytical, theoretical, biochemistry
atomic radius
one-half the distance between the nuclei of identical atoms that are bonded together. increases to the bottom and left
electronegativity
the tendency of an atom or a functional group to attract electrons towards itself. increases up and right
ionization energy
the amount of energy required to remove an electron from an isolated atom or molecule. increases up and right
electron affinity
the amount of energy released when an electron attaches to a neutral atom to form a negatively charged ion. increases up and right
period
The horizontal rows of chemical elements on the periodic table. Every element in a period have the same number of electron shells
group/family
The vertical columns of chemical elements on the periodic table. Each element in a group/family has the same number of valence electrons and have similar chemical and physical properties
precision
repeatable and reliable
accuracy
a correct measurement
homogeneous mixture
composition is uniform throughout, can’t be pulled apart. ex. juice, glue, milk
heterogenous mixture
composition is not uniform, can be pulled apart. ex. salad, chicken soup, sandwich
how to read a caliper
Line up jaws, keep big number, first aligning small number is decimal
Steps for scientific method
Observation, hypothesis, experiment, data analysis, conclusion (OH EDAC)
metals
good conductors for heat and electricity
nonmetals
poor conductors for heat and electricity
noble gases
inert, very stable, don’t form compounds
halogens
non-metals, strong odor, don’t dissolve well, react with most non-metals and metals
alkali metals
1 valence electron, very reactive, soft, stored under oil. form cations
alkaline earth metals
2 valence electrons, not as soft or reactive as alkali metals. form cations
Note
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