CHEMISTRY REGENTS OVERVIEW

PROTONS
POSITIVELY CHARGED (+)
NEUTRONS
NO CHARGE
ELECTRONS
– ARE SMALL AND ARE NEGATIVELY CHARGED(-)

– FOUND IN “CLOUDS” ORBITALS AROUND AN ATOM’S NUCLEUS

NUCLEONS
PROTONS AND NEUTRONS THAT ARE IN AN ATOM’S NUCLEUS
MASS NUMBER
– IS EQUAL TO AN ATOM’S NUMBER OF PROTONS AND NEUTRONS ADDED TOGETHER
ATOMIC NUMBER
– equal to the # of protons in the nucleus of an atom
NUMBER OF NEUTRONS
– equal to mass number – atomic number
ISOTOPES
– atoms with equal number of protns, but diifer in neutron number
CATIONS
– positively charged ions (+)

– forms when a neutral atom loses electrons

– smaller than their parent atom (anion)

ANIONS
– negatively charged ions (-)

– forms when a neutral atom gains electrons

– larger than their parent atom (cations)

ERNEST RUTHERFORD – GOLD-FOIL EXPERIMENT
– showed that an atom is consisted of empty space with a small, dense, positively charged nucleus
DALTON’S MODEL OF ATOM
– showed solid sphere of matter that was uniform throughout
BOHR MODEL OF ATOM
– in model of atom, placed electrons orbiting around the nucleus
CURRENT WAVE – MECHANICAL MODEL
– shows atoms with electrons in clouds around the atom’s nucleus
STP
– standard temperature & pressure (273 kelvin and 1 atm)
BRIGHT LINE SPECTRA
– electrons emit energy as light when they jump from the higher energy levels back to the ground state.
ELEMENTS
– pure substances composed of only one kind of atom
BINARY COMPOUNDS
– substances made up of two kinds of atoms (ex: H20, NH3, CO2)
DIATOMIC COMPOUNDS
– elements that form two atom molecules in their natural form at STP

* REMEMBER THE PHRASE – ” BrINCIHOF”
(BR2, I2, N2, CL2, H2, O2, F2)

SOLUTIONS
homogenous mixtures (air, salt water, etc.)
HOMOGENOUS
– A class of matter with definite properties whose members are composed of two or more substances, each retaining its own identifying properties (e.g., mixed vegetables).
HETEROGENEOUS
A heterogeneous compound, mixture, reaction or other such object is one that consists of many different items, which are often not easily sorted or separated, though they are clearly distinct.
SOLUTE
– substance being dissolved
SOLVENT
– substances that dissolves the solute
PHYSICAL CHANGES
– do not from new substances

– merely change the appearance of the original substance (melting of ice)

CHEMICAL CHANGES
– results in the formation of new substances (ex: the burning of hydrogen gas to produce water vapor)
REACTANTS AND PRODUCTS
– REACTANTS = left side of the reaction arrow

– PRODUCTS = right side of the reaction arrow

ENDOTHERMIC REACTIONS
– absorb heat

– the energy value is on the left side of the reaction arrow in a forward reaction

EXOTHERMIC REACTIONS
– releases energy

– energy is the product in the reaction

SYNTHESIS REACTIONS
– when two or more reactants combine to become one
DECOMPOSITION REACTIONS
– occurs when a single reactant forms two or more products
SINGLE REPLACEMET REACTIONS
– when one element replaces another element in a compound
DOUBLE REPLACEMENT REACTIONS
– occurs when two compounds react to form to new compounds
LAW OF CONSERVATION OF MASS
– masses of reactants = masses of products
GRAM FORMULA MASS
– sum of the atomic masses of all the atoms in a substance
Use this diagram to help determine the number of significant figures in a
measured value…
Pacific Atlantic

If the decimal point is present, start counting digits from the Pacific (left) side,
starting with the first non-zero digit.
1 2 3
0.00310 (3 sig. figs.)
If the decimal point is absent, start counting digits from the Atlantic (right) side,
starting with the first non-zero digit.
3 2 1
31,400 (3 sig. figs.)

ELECTRON CONFIGURATION
Electron configurations are written in the bottom center of an element’s box on the
periodic table in your reference tables.

# of electrons in 3rd principal energy level
# of electrons in 2nd principal energy level
# of electrons in 1st principal energy level

ISOTOPES
Isotopes are written in a number of ways: C-14 is also Carbon-14, and is also
mass number 14C
atomic number 6
SOLIDS
– definite shape and volume
LIQUIDS
– no definite shape, but definite shape
GASES
– no definite shape or volume

– random particle motion

SUBLIMATION
– substances that turn from a solid directly to a gas (CO2, I2)
SUBLIMATION
– substances that turn from a solid directly to a gas (CO2, I2)
DEGREES KELVIN
– C + 273
HEAT OF FUSION
– the heat absorbed or released when 1 gram of substances changes from a solid to liquid phase
HEAT OF VAPORIZATION
– heat absorbed or releases when 1 gram of substance moves from liquid phase to gas phase
PRESSURE/VOLUME
– pressure of gas increases, volume decreases

– pressure of gas decreases, volume increases

REAL GASES
– real gas particles have volume

– attracted to one another

– not behave like ideal gases

– will behave like ideal gases under low pressure and high temp.

DISTILLATION
– SEPARATING MIXTURES WITH DIFFERENT BOILING POINTS
FILTRATION
– separating mixtures of solids and liquids

-chromotography can also be used

NOBLE GASES (GROUP 18)
– (GROUP 18) – inert and stable
IONIZATION
– increases as you GO UP AND TO THE RIGHT OF TABLE
ATOMIC RADII
– decreases left to right

– due to increasing nuclear charge

– increases as you go downa group

ELECTRONEGATIVITY
– measure of an element’s attractions to electrons
ALKALI METALS
– Group 1
ALKALINE EARTH METALS
– Group 2
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