49 Cards in this Set
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Chemistry
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Study of matter and it's transformations
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Matter
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Is anything that has mass and takes up space
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Element
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Substance that cannot be changed by chemical reaction into more substances; purest form
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Compound
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Substance contains two or more elements
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Atom
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The smallest particle of an element that embodies the chemical properties of that element
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Molecule
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Collection of atoms connected by bonds
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Chemical symbol
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The one of two letter abbreviation for the name of an element
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Chemical formula
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Symbols of different kinds of atoms written together with subscripts showing how many atoms of each kind are in a molecule
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Modern atomic theory
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All matter is composed of atoms
All atoms of a particular element have the same chemical properties
Compounds are formed by the chemical combination of two or more different kinds of atoms
A chemical reaction involves joining, separating, or rearranging atoms
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Metals
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Good conductors
Lustrous
Ductile
Malleable
Solids at room temp except for mercury
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Nonmetals
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Do not conduct electricity
Mostly gases
Carbon, phosphorus, sulfur, selenium, and iodine are brittle solids
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Metalloids
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Lustrous
Less conductive than metals
Brittle
B, Si, Ge, As, Sb, Te
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Groups
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Aka as columns of periodic table; families
Similar reactivity going down
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Periods
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Aka the rows of a periodic table
Similar size across the row
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Nucleus
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Is the total number of protons and neutrons
Accounts for most of the atom's mass
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Atomic number
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The number of protons in an atoms nucleus
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Mass number
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The number of protons in an atoms nucleus
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Isotopes
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Atoms with the same atomic number but different mass number(same element but different neutrons)
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Isotopic mass
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The mass of a particular isotope of an element
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Percent abundance
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The percentage of an element that comes from a particular isotope
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Atomic weight
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The weighted average of the isotopic masses of an element
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Frequency
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The number of complete waves passing a point in a given amount of time
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Planck's theory
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He explained the changes in light emitted from an object being heated
Light energy comes in small energy packets called quanta
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Photoelectric effect
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Certain metals eject electrons when irradiated with special wavelengths of light
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Heisenberg uncertainty principle
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It's impossible to know the exact position And exact momentum of an object simultaneously
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Heisenberg uncertainty principle
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n
Determines relative energy and orbital size
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Subsidiary quantum number
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L. Can be a positive number (n-1)
Angular momentum number
Determines orbital shape
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Magnetic quantum number
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Ml from negative l to positive l
Determines orientation
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Spin quantum number
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Ms can be +1/2 or -1/2
Determines spin of electron in atomic orbital
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Aufbau principle
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Orbitals are filled to give the lowest total energy for the atom
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Pauli exclusion principle
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No two electrons can have the same 4 quantum numbers
If one electron is spin up the other has to be spin down
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Hund's rule
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Electrons pair only after each orbital in a subshell contains an electron
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Core electrons
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Electrons in an atoms inner energy levels
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Valence electrons
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Electrons in an atoms outermost energy level
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Net charge
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(# of protons) - (#of electrons)
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Cation
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Positively charged ion
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Anion
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Negatively charged ion
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Monatomic ion
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Is formed when an atom either gains or loses an electron
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Diamagnetic
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Substances that have filled subshells and all their electrons are paired
Doesn't respond to magnets
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Paramagnetic
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Substances that have unpaired electrons; will react to magnetic field
Strength of magnetic attraction is proportional to number of unpaired electrons
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Isoelectronic ions
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Ions with the same electronic structure
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Atomic radii
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Atomic radius is determined by measuring the distance between the two identical nuclei and dividing by 2
-right to left increasing radius
-down a group it increases
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Effective nuclear charge
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The nuclear positive charge experienced by outer shell electrons
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First ionization energy
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The energy needed to remove the most weakly bound electron from a neutral atom in the gas phase
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Electron affinity
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Amount of energy absorbed when e- is added to an atom
Increases as you go down a group
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Covalent bonds
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Energy is minimized while attractive and repulsive forces are balanced in covalent bonds
Usually occurs when the difference in electronegativity between atoms is small
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Organic molecular compound
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A molecular compound that contains carbon
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Inorganic molecular compound
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A molecular compound that does not contain carbon
Exceptions are CO and CO2
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Octet rule
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Main group atoms with more than two valance electrons gain, lose or share electrons to attain an octet of valance electrons
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CH 115: MOLECULAR FORMULAS & NAMES