chemical bonding
the joining of atoms to form new substances
chemical bond
the force of attraction that holds two or more atoms together
theory
idea that explains something and is supported by data
valence electrons
electrons on the outermost energy level of an atom
if you know the groups, you know the # of valence electrons!
they're responsible for chemical bonding
atoms "want" to be stable
ionic bonds
the force of attraction between two oppositely charged ions
usually between metals/non-metals
ions
electrically charged atoms that have gained or lost electrons.
polyatomic ions
ions that are made of more than one atom
oxidation
loss of electrons
reduction (or redox)
gain of electrons
oxidation number
the amount of electrons that will be gained or lost; the final charge
redox reaction
EX.
Na + F --> Na+ + F- --> NaF
Na has been oxidized/F has been reduced
crystal lattice
a repeating three-dimensional pattern of ions formed by ionic compounds
covalent bond
a bond formed by the sharing of electrons between atoms
usually between non-metals
diatomic molecule
the simplest molecules- two atoms of the same element bonded together
all gasses are found diatomically
"di" means two
EX. O2, Cl2, F2
hydrogen bond
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molecule
the simplest particle of a covalent compound
metallic bond
the force of attraction between a positively (+) charged metal ion and the electrons in a metal
valence levels overlap, so some electrons can move freely throughout the metal
the better the flow of electrons = the better conductor it is
chemical reaction
the process by which one or more substances change to produce one or more different substances
chemical formula
a combination of chemical symbols and numbers to represent a substance
subscript
the small number written to the lower right of a chemical symbol
chemical equation
a short, easy way to show a chemical reaction, using symbols instead of words
reactants
the starting materials in a chemical reaction; starting substances
products
ending materials in a chemical reaction
coefficients
the numbers that are placed in front of the formulas in an equation in order to balance it; acts like a multiplier
law of conservation of mass
the law that states that mass cannot be created or destroyed in ordinary chemical and physical changes
least common multiple
...
synthesis reaction (or composition)
a reaction in which two or more substances combine to form a new compound
EX. 2Na + Cl2 --> 2NaCl
decomposition reaction
a reaction in which a single compound breaks down to form two or more simpler substances
EX. H2CO3 --> H2O + CO2
single-replacement reaction
a reaction in which an element takes the place of another element that is part of a compound
EX. Zn + 2HCl --> ZnCl2 + H2
double-replacement reaction
a reaction in which ions in two compounds switch places
products of the reaction is often a gas or precipitate (solid)
EX. NaCl + AgNO3 --> NaNO3 + AgCl
exothermic
a chemical reaction in which energy is released or removed; primarily given off in the form of heat
"exo" go out/exit "thermic" heat/energy
endothermic
a chemical reaction in which energy is absorbed
"endo" go in "thermic" heat/energy
law of conservation of energy
the law that states that energy cannot be created or destroyed
activation energy
the minimum amount of energy required to start a chemical reaction
catalyst
substance that speeds up the rate of a chemical reaction
inhibitor
a substance that slows down or stops a chemical reaction
ionic compound
a compound composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal
forms a crystal lattice
covalent compound
a chemical compound formed by the sharing of electrons
acid
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hydronium ion
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base
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hydroxide ion
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pH
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litmus paper
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salt
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organic compound
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biochemicals
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carbohydrates
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lipids
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proteins
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nucleic acids
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hydrocarbons
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hydrophilic
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hydrophobic
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cations
atoms that lose electrons and end up being positively charged
EX. Na+
anions
atoms that gain electrons and end up being negatively charged
EX. F-
clues to chemical reactions
gas formation
solid formation - sometimes formed when two solutions react, creating a precipitate
color change
energy change - sometimes energy is released during reactions
factors affecting rates of reaction
temperature - an increase in temp increases the rate of a reaction b/c at higher temps, particles of reactants move faster, so they collide with each other more frequently with more energy
concentration - an increase in concentration increases the rate of