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152 Cards in this Set
- Front
- Back
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Molecular Compounds
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Atoms held together by covalent bonds.
No charge. |
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Molecular Formulas
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Tell how many of each type of atom are in a compound.
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Ionic Compound Formula
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Describes ratio of ions in the compound.
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Covalent Bond
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Atoms held together by joined electrons.
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Molecule
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Neutral group of atoms joined together by covalent bonds.
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2 Molecular Compound Properties
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1. no flow of electrons
2. low melting and boiling points |
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Molecular Structure
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arrangement of atoms within a molecule
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Octet Rule
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Covalent compounds are most stable when each atom has eight electrons.
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Covalent Bond: Single
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One shared electron pair, with one electron from each atom.
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Covalent Bond: Double
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Two shared electrons pairs, with two electrons from each atom.
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Covalent Bond: Triple
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Three shared electron pairs, with three electrons from each atom.
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Coordinate Covalent Bonds
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~One atoms contributes both electrons in the bonding pair.
~One atom may contribute a pair of un-shared e- to a bond to give both atoms an inert gas configuration. ~Can also occur in poly-atomic ions, such as NH4+ |
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Exceptions to Octet Rule
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Molecules w/ an odd # of valence e- can't follow octet
Some molecules w/ an even # of e- fail to follow octet rule |
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Bond Dissociation Energies
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~Large bond dissociation energy = strong cov. bond
~Double and triple bonds stronger than single bonds ~Reactivity linked to strength/weakness of cov. bonds |
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Resonance
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~ Possible e- dot structures called resonance forms
~E- pairs do not move back and forth b/w resonance forms |
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Binary Molecular Compounds
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~consist of two nonmetals
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Prefixes
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~show number of atoms of each element in a molecule of the compound
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Naming Binary Molecules
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~use subscripts in formula to find prefixes for each nonmetal
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VSEPR Theory
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valence shell e- pair repulsion theory: e- pairs - because neg charged- arrange themselves as far away from each other in a 3D space
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Prefixes
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Mono- 1 Hexa- 6
Di- 2 Hepta- 7 Tri- 3 Octa- 8 Tetra- 4 Nona- 9 Penta- 5 Deca- 10 |
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VSEPR Step 1
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Draw Lewis Dot Structure
-satisfy octet or duet rule -exceptions: Be, B (fewer) > only can't octet S, P (more) > if satisfy rule -Halogens and H only form single bonds |
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VSEPR Step 2
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Look At Central Atom
-identify the number of bonds and number of ion e- pairs l_ multiple bonds count as 1 -identify shape; angle |
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Shapes and Angles
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Tetrahedral: central atom w/ 4 B 109.5
Trig. Pyr.: 3 B 107 Bent: 104.5 Tigonal Planar: flat, no ion 120 Linear: 180 |
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mass
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amount of matter an object contains
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volume
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measure of space occupied by an object
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extensive property
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property that depends on amount of matter
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intensive property
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a property that depends on the type of matter
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substance
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matter with a uniform and definite composition
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physical property
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a quality/condition of a substance that may be observed or measure without changing the substance's comostion
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solid
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matter with definite shape and volume
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liquid
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matter with indefinite shape and definite volume
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gas
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matter with indefinite shape and volume
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vapor
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gaseous state of a substance the is most often a liquid or solid at room temperature
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physical change
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some properties of the substance change, but the composition does not
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mixture
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physical blend of two or more components
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heterogeneous mixture
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non uniform mixture
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homogeneous mixture
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a mixture that is uniform throughout
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solution
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another name for homogeneous mixture
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phase
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used to describe any part of an example with uniform composition and qualities
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filtration
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the process of separating the solid from the liquid in a heterogeneous mixture
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distillation
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liquid is boiled to produce a vapor then condensed back into a liquid
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element
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simplest form of matter with a unique set of properties
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compound
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substance that contains two or more elements chemically combined in a fixed proportion
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chemical change
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a change that produces matter that has a different composition than the original
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chemical symbol
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one or two letters, first letter capital second letter lowercase
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periodic table
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an arrangement of elements in which elements are set in to groups based on a set of repeating properties
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period
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horizontal row of periodic table
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group
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vertical column of periodic table
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chemical property
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ability of an element to undergo a specific chemical change
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chemical reaction
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one or more substances changing into one or more new substances
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reactant
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substance present at start of reaction
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product
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substance produced in the reaction
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precipitate
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solid that forms and settles out of a liquid mixture
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law of conservation of mass
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in any physical change or chemical reaction energy is preserved
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three states of matter
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solid, liquid, gas
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physical changes can be classified as??
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reversible or irreversible
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True/False
Every sample of a given substance has identical intensive properties because every sample has the same composition |
True
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Two types of mixtures?
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Heterogeneous and Homogeneous
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True/False
Similarities in physical properties can be used to separate mixtures. |
False
Differences in physical properties. |
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True/False
Elements can be broken down into simpler substances, but compounds cannot. |
False
Compounds can elements cannot |
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Fixed composition:
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substance
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Varying composition:
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mixture
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True/False
During a chemical change the composition of matter never changes. |
False
It always changes |
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4 Possible Clues to chemical change:
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~Transfer of energy
~Change in color ~Formation of a precipitate ~Production of a gas |
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measurement
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quantity that has both number and unit
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scientific notation
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given number is written as product of two numbers: a coefficient and a 10 raised to a power
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Accuracy
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measure of how close a measurement comes to the actual or true value of whatever is being measured
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Precision
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measure of how close a series of measurements are to one another,irrespective of the actual value
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Accepted value
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correct value for measurement based on reliable references
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experimental value
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the value measured in the lab
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error
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difference between experimental and accepted value
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error equation
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Error= experimental value - accepted value
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percent error
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absolute value of error divided by accepted value, multiplied by 100%
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Percent error equation
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lerrorl
Percent Error= ------------------- x 100% accepted value |
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Sig Figs
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includes all digits known, as well as a last digit that is estimated
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Conversion factors
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ratio of equivalent measurements
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Dimensional analysis
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a way to analyze and solve problems using the units or dimensions of the measurements
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True/False
In scientific notation, the coefficient is always greater than or equal to one and less than ten. The exponent is an integer. |
True
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True/False
To evaluate accuracy, the measured value must be compared to the correct value. To evaluate the precision of a measurement, you must compare the values of two or more repeated measurements. |
True
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True/False
Measurements must always be reported to the correct number of sig figs because calculated answers always depend on the number of sig figs in the values used in the calculation |
True
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True/False
All metric units are based on multiples of 5 therefore you can convert between units easily |
False
Based on multiples of 10. |
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True/False
Scientists commonly use two equivalent units of temperature, the degrees Celsius and Fahrenheit. |
False
Celsius and kelvin |
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True/False
Density is an intensive property that depends only on the size of the sample, not the composition of the substance. |
False
Depends on the composition of the substance, not the size of the sample. |
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True/False
When a measurement is multiplied by a conversion factor, the numerical value changes, and the actual size of the quantity measured also changes. |
False
The actual size of the quantity measured stays the same. |
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True/False
Dimensional analysis is a powerful tool for solving conversion problems in which a measurement with one unit is changed to an equivalent measurement for another unit. |
True
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atom
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the smallest particle of an element that retains its identity in a chemical reaction
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Dalton's atomic theory
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1. All elements are composed of tiny indivisible particles called atoms
2.Atoms of the same elements are identical. The atoms of any one element are different from the atoms of any other element. 3.Atoms of different elements can physically mix or chemically combine into simple whole number ratios to form compounds 4. chem reactions occur when: atoms are separated, join, or are rearranged. |
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Thomson's Model
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Plum Pudding Model
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Rutherford's Model
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Gold Foil Experiment, discovered nucleus.
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Bohr's Model
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Electrons in specific orbits
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Quantum Mechanical Model
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Current model, cannot know speed and location of e- at same time, e- do not travel in predictable orbits, e- located in orbitals, movement of e- is random
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orbitals
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3D regions outside nucleus where e- are found
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electron
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negatively charged subatomic particles
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cathode ray
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glowing beam, electrons are inside that travel from cathode (negative) to anode (positive).
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proton
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positively charged subatomic particle
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neutron
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subatomic particle with no charge, same mass as a proton
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nucleus
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tiny central core of atom composed of protons and neutrons
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atomic number
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number of protons in the nucleus of the atom of that element
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mass number
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total number of protons and neutrons in an atom
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How to find # of neutrons?
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# Neutrons = mass # - atomic #
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Isotope
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atoms with same number of protons but different number of neutrons
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atomic mass unit (amu)
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defined as 1/12th of the mass of a carbon-12 atom.
Ex: Helium-4 atom is 1/3 mass of C-12 atom Nickel-60 atom is 5 times the mass of C-12 |
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valence electrons
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e- in the outer shell of the atom
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electron dot structure
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diagrams that show valence electrons in the atoms of an element as dots
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halide ion
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ions produced when atoms of chlorine and other halogens gain electrons
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ionic bond
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compound composed of cations and anions
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chemical formula
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shows number of atoms of each element in the smallest representative unit of a substance
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metallic bond
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forces of attraction between free floating valence electrons and the positively charged metal ions
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alloy
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mixture of two or more elements, at least on of which is a metal
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True/False
To find the number of valance electrons for an atoms of a representative element, simply look at its period number. |
False
Group Number |
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True/False
A positively charged ion, or cation, is produced when an atom gains one or more valence electrons. |
False
When it loses one or more valence electron. |
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True/False
An anion is produced when an atom gains one or more valence electrons. |
True
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True/False
Ionic compounds are electrically neutral. |
True
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True/False
Most ionic compounds are not crystalline solids at room temperature. |
False
Most ionic compounds are crystalline solids at room temperature. |
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True/False
Ionic compounds generally have low melting points. |
False
Generally high melting points. |
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True/False
Ionic compounds can conduct an electric current when melted or dissolved in water. |
True
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True/False
The valence electrons of atoms in a pure metal can be modeled as a sea of electrons. |
True
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True/False
Alloys are important because their properties are often superior to those of their component elements. |
True
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Diatomic Molecule
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a molecule that contains two atoms
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Structural Formula
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represents covalent bonds as dashes and shows the arrangement of covalently bonded atoms.
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un-shared pair of electrons
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pair of valence electrons not shared between atoms
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Polyatomic Ion
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tightly bound group of atoms that has a positive or negative charge and behaves as a unit
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True/False
A molecular formula show how many atoms of each element a substance contains. |
True
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True/False
The representative unit for a molecular compound is a molecule. The representative unit for an ionic compound is also a molecule. |
False
The ionic compound representative unit is a formula unit. |
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True/False
In a coordinate covalent bond, the shared electron pair come from a single atom. |
True
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True/False
The octet rule is not satisfied in molecules with an odd number of valence electrons and in molecules in which an atom has less, or more, than a complete octet of valence electrons. |
True
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True/False
In order to explain the 3D shape of molecules, scientists use the octet rule. |
False
Scientists use the valence-shell electron-pair repulsion theory (VSEPR theory) |
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energy levels
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fixed energies an electron can have
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quantum
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amount of energy to required to move an electron from one energy level to another.
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atomic orbital
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probability of finding an electron at various points around the nucleus
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electron configurations
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ways in which electrons are arranged in various orbitals around the nuclei of atoms
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aufbau principle
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electrons occupy the orbitals of lowest energy first
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Pauli exclusion principle
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atomic orbital may describe at most 2 electrons, electrons occupying an orbital together must have opposite spins
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spin
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quantum mechanical property of electrons, clockwise or counter clockwise
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Hund's rule
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most elctrons possible with same spin
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amplitude
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wave's height from 0 to crest
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wavelength
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(weird upside down y symbol) distance b/w crests
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frequency
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(symbol v) # of wave cycles to pass a given point per unit of time unit= cycles per sec or hertz
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hertz (Hz)
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SI unit of cycles per second
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Electromagnetic radiation
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radio waves / microwaves / infrared waves / visible light / ultraviolet waves / X-rays / gamma rays
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C / or product of frequency and wavelength
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c= (upside down y)(v)
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atomic emission spectrum
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made up of wavelengths of spectral lines
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Planck's constant
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the constant -h with a value of 6.626 x 10^-34 J
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Planck's equation
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E= hv
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photoelectric effect
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electrons ejected when a light shines on a metal
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photons
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light quanta
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ground state
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when electron has lowest possible energy
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Heisenberg uncertainty principle
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impossible to know velocity and position of a particle at the same time
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atomic radius trend
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increases - top to bottom
decreases- left to right |
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ionization energy
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Decrease- top to bottom
increase- left to right |
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ionic size
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increase- top to bottom
decrease- left to right |
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Electronegativity
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decrease- top to bottom
increase- left to right |
