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63 Cards in this Set
- Front
- Back
atom
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the smallest unit of a chemical element, consists of a nucleus and one or more electrons
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nucleus
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the center of an atom, contains protons and neutrons
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electron
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negatively charged, with a mass of 0
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proton
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positive charge, mass of about 1, the number of protons in the nucleus of an atom determine its element
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neutron
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mass about i amu,no electrical charge
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mass
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measures the quantity of matter present; the greater the mass, the greater the quantity of matter present
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atomic mass unit (dalton)
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the mass of a proton serves as a standard unit of measure: amu
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gram
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a measure of mass
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charge (positive, negative, neutral)
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e- have a negative charge, P+ have a positive charge and No have a neutral charge, unlike charges attract each other, like charges repel each other, atoms are electrically neutral
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element
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a pure substance that contains only one type of atom
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periodic table
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groups the elements according to their physical and chemical properties
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period
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horizontal rows, correspond to the number of electron shells in the atom
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group
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horizontal column, have elements with similar properties
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atomic number
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tells the number of protons
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mass number (or atomic mass)
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tells the number of P+ plus the number of No averaged over all isotopes
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chemical symbol
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the name of the element
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isotope
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isotopes of the same element all have the same, definitive, number of protons but differ in the number of nuetrons in the atomic nucleus
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atomic mass
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tells us the # of P+ plus the # of No
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radioisotope, radioactivity
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loss of energetic particles from an unstable nucleus, Three types:
Alpha: 2 protons, 2 neutrons (He nucleus);Has mass Beta: an electron (from the nucleus);Note: a neutron can become and proton due to beta decay—resulting in a change in the number of protons in a nucleus Gamma:Has no mass, pure energy |
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electron shell
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e- orbitals constitute a series of e- shells, or energy levels, around the nucleus, the innermost shell consists of only one orbital, the s orbital, the second shell is made up of 4 orbitals, an s orbital and three p orbitals, and hence can hold up to 8 electrons
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electron orbital
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the region of space where the e- is found at least 90% of the time, the s orbital fills with e- first, a given orbitalcan be occupied by at most 2 electrons
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chemically stable elements
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when there are no unpaired electrons in the outermost shell, will not react eith other atoms, nobel gases
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reactive atoms
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have unpaired e- in their outermost shell, seek to attain the stable condition of having no unpaired e- in their outermost shell, acheive this by sharing e- or gaining or losing e-
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molecule
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two or more atoms linked together by chemical bonds
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octet rule
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the tendency of atoms in stable molecules to have 8 e- in their outermost shells
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chemical bond
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an attractive force that links two atoms together to form a molecule
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covalent bond
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the strong bond that results from the sharing of e-, quite stable because bonds are hard to break, bonds are the same in length, angle and direction reguardless of the larger molecule of which the particular bond is a part of
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molecular weight
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the sum of the atomic weights of all atoms in the molecule, ususally realted to a molecules size
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structural formula
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shows the chemical names of the elements and how many bonds are holding each atom
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electronegativity
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the attractive force that an atom exerts on electrons, more P= means more electronegative and the closer the e- are to the nucleus the more electronegative an atom is
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nonpolar covalent bond
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the atoms have the same electronegativities so the e- are shared equally
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polar covalent bond
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the atoms have differing electronegativities so the e- are unequally shared
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partial unit of charge, “delta,” δ
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result from polar covalent bonds because of the unequal sharing of e-, occur at the ends
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hydrogen bond
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a weak bond, Forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom
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ion
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electrically charged particals that form when atoms gain or lose one or more e-
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cation
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positively charged ions
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anion
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negatively charged ions
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ionic bond
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bonds formed by chemical attraction etween ions bearing opposite charges
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hydrophilic
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"water-loving", having an affinity for water, polar molecules
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hydrophobic
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"water-hating", having no affinity for water,uncharged and nonpolar groups of atoms
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chemical reaction
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Is the making and breaking of chemical bonds,
Leads to changes in the composition of matter, bonding partners and energy may change in a chemical rxn |
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reactant
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on the left side of the equation, what form the product(s)
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product
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on the right side of the equation, formed by the reactant(s)
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energy
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the capacity to do work, the capacity for change
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potential energy
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the energy that is possible
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calorie
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the amount of heat energy needed to raise the temperature of 1 gram of pure water 1 degree celcius
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solution
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produced when a substance is dissolved in a liquid
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solute
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the substance that is being dissolved
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solvent
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the substance that is doing the dissolving
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aqueous
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a sloution formed when the slovent is water
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mole
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the amount of an ion or compound(in grams) whose weight is neumerically equal to its molecular weight
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Avogadro’s number
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6 x 10^23, a constant that realtes the weight of any substance to the # of molecules of that substance
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molar solution
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1 mole of a substance dissolved in water to make 1L
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molarity
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the number of moles of solute per liter of solution
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acid
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a substance that release hydrogen ions
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base
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substances that attach to hydrogen ions
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reversible reaction
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a reaction that can proceed in etiher direction depending on the relative starting concentrations of the reactants and products, written using a double arrow
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strong acid or strong base
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dissolve fully into its ions in water
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weak acid or weak base
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does not dissicociate completely in water
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pH
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the measure of the H+ concentration of a sloution, scale from 1-14, 7 being neutral, 1 being most acidic, 14 being most basic
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buffer
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chemical mixtures that maintain a relativelt constant pH even when substantial amounts of an acid or base are added
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functional groups
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each functional group has specific properties that, when attached to a larger molecule, in turn give the larger molecule specific properties, ones we need to know,
OH is polar; molecule becomes more hydrophilic -COOH releases hydrogen ion (H+) in solution, increasing the [H+] of the solution; acts as an acid; COO–(is negatively charged) -NH2 the “N” will attract a third hydrogen to itself, so that this group reduces the [H+] of the solution (acts as a base);N+H3 (is positively charged) |
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isomers
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molecules with the same
chemical formula, but with the bonds rearranged , 2 types: structural(differ in how thier atoms are joined together) and optical(two isomers that are mirror images of each other) |