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48 Cards in this Set
- Front
- Back
What is organic chemistry
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The chemistry of compounds that contain the element carbon
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What is a compound?
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It is made up of elements combined in different proportions.
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Elements are made up of
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Atoms
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Atoms are made up of
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a dense, positively charged nucleus containing protons and neutrons and are surrounded by a cloud of electrons.
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The mass of an atom is made up by what
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Neutrons and Protons which have nearly the same mass of 1 atomic mass unit each. They are 1800 times as heavy as an electron
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What makes up most of the volume of an atom?
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The volume occupied by the electrons is 10,000 times larger than that of the nucleus.
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The atomic number (Z) above the element is
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equal to the number of protons in its nucleus and number of electons surrounding it's nucles.
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What are isotopes
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Atoms of the same element that have different masses because they have different number of neutrons.
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How many electrons does an atom have in its valence shell?
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We look at the periodic table, the number of electons in the valence shell is equal to the group number of the atom.
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What are isomers?
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Different compounds that have the same molecular formula
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What kind of bonds can the following atoms make what type of fixed number of bonds:
Carbon Oxygen Hydrogen and halogen atoms |
Carbon is tetravalent, 4 bonds
Oxygen is divalent, 2 bonds Hydrogen and Halogen atoms are monovalent and can make 1 bond. |
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What are constitutional isomers, how doe they differ
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different compounds with the same molecular formula but differ in the sequence in which their atoms are bonded, that is in their connectivity. ( They differ in their melting point, boiling point and density) and they have different chemical properties (reactivity).
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What are the two major types of chemical bonds? define them.
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Ionic (or electrovalent) bonds are formed by the transfer of one or more electrons from one atom to another to create ions.
Covalent bonds result when atoms share electrons. |
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Atoms that gain or lose electrons and form charged particles are called
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Ions
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An ionic bond is:
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an attractive force between oppositely charged ions, one source of such ions is a reaction between atoms of widely differing electronegativety.
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what is electronegativity?
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a measure of the ability of an atom to attract electrons. It increases as we go across a horizontal row of the PT from left to right and as we go up a verticle column
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How to salts form?
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Salts form only when atoms of very different electronegativities transfer electrons to become ions
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how do covalent bonds form, what happens to the atoms?
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Covalent bonds form by sharing of electrons between atoms of similar electronegativities to achieve the configuration of a noble gas.
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What is composed of atoms joined exclusevely or predominantly be covalent bonds?
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Molecules.
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How do you calculate "Formal Charge"
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F = Z - (1/2)S - U
Valence - a (1/2) shared - unshared |
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Resonance theory states that:
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whenever a molecule or ion can be represented by two or more lewis structures, none of these structures is a realistic representation of the molecule or ion. Instead, the actual molecule or ion will be better represented by a hybrid (average) of these structures.
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What is the difference between resonance and equilibrium?
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Resonance is represented by a two arrows, resonance by a two sided arrow indicating that it only exists on paper while equilibrium is different structures moving ( or fluctuating) atoms. Resonance atoms do not move.
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Wave Function corresponds to
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a different energy state for an electron
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How can the energy associated with an electron be calculated?
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by its wavefunction
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the probability of finding an electron in a given region can be calculated by
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the wave function
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Occurs when wave functions with the same phase sign interact. There is a reinforcing effect and the amplitude of the wave function increases
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Constructive Interference
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Occurs when wave functions with opposite phase signs interact. There is a subtractive effect and the amplitude of the wave function goes to zero or changes sign
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What is Destructive interference
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Is a region of space where the probability of finding an electron is high
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What is the orbital
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are plots of (wavefunction square) in three demensions
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what are atomic orbitals
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which principle state that orbitals of lowest energy are filled first?
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Aufbau principle (german for "building up")
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Principle that states that a maximum of 2 electrons may be placed in each orbital but only when spins of the electrons are paired
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What is the Pauli exclusion principle
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Orbitals of equal energy such as the three 2p orbitals are called
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degenerate orbitals
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Rule that states that first you add electrons to degenerate orbitals with spins unpaired so that they have maximum separation, then you begin to add the second electron so the spins are paired
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What is Hund's rule
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principle that states that we cannot simultaneously know the position and momentum of an electron
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The Heisenberg uncertainty principle
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Represents the region of space where one or two electrons of an isolated atom are likely to be found
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atomic orbital
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Represents the region of space where one or two electrons of a molecule are likely to be found
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molecular orbital (MO)
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results when two orbitals of the same phase overlap
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what is a bonding molecular orbital
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results when two orbitals of opposite phase overlap
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what is antibonding molecular orbital
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All purely single bonds are
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sigma bonds
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All purely single bonds are
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sigma bonds
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Hydrocarbons whose molecules contain a carbon-carbon double bond are called
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alkenes. Ethene (C2H4) and propene (C3H6) are both alkenes.
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What is the region of space about the nucleus of a single atom with the high probability of finding an atom
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Atomic Orbital (AO)
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when Atomic Orbitals Overlap, they combine to form ...
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Molecular Orbitals
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Is the Energy of Electrons in the bonding molecular orbital has more or less energy than the energy of the electrons in their separate atomic orbitals
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less
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Is the Energy of Electrons in the anti-bonding molecular orbital has more or less energy than the energy of the electrons in their separate atomic orbitals
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more
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The number of molecular orbitals is equal to
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the number of atomic orbitals from which they are formed. Combining two atomic orbitals will always yield two molecular orbitals, one bonding and one anti-bonding
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Hybrid atomic orbitals are obtained by
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mixing (hybridizing) the wave functions for orbitals of different types (s & p orbitals) from the same atom
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True or False
Atoms joined by single bonds can rotate relatively freely with respect to one another |
True
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