Term
| What are the energy changes when a chemical bond is formed? |
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Definition
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Term
| What are the energy changes when a chemical bond is broken? |
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Definition
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Term
| Electronegativity difference |
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Definition
| A number found by taking the difference between the electronegativities of two atoms in a bond. Its value determines the type of bond. |
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Term
| Describe an ionic bond in terms of electronegativity difference. |
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Definition
| When the electronegativity values, EN differ by 1.7 or more, the atom with the higher EN borrows the bonding electrons from the atom with lower EN. Resulting positive and negative ions attract. |
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Term
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Definition
| When the electronegativity difference is very small (less than 0.5), two bonded atoms share the valence e-. The resulting molecule has no electrostatic charge. |
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Term
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Definition
| When the electronegativity difference is between 0.5 and 1.7, bonding electrons stay closer to the more electronegative atom. Electrons are shared unequally. |
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Term
| Describe a non-polar molecule with polar bonds. |
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Definition
| When the polar covalent bonds are arranged symmetrically around the central atom. e.g. CO2, CH4, CCl4 |
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Term
| Coordinate covalent bonds |
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Definition
| When both electrons in a covalent bond are supplied by one atom. |
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Term
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Definition
| A sea of electrons surrounding positive metal ions. |
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Term
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Definition
| intermolecular forces (forces between molecules) |
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Term
| List three types of Van der Waals forces |
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Definition
| dipole-dipole attraction london dispersion forces hydrogen bonds |
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Term
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Definition
| Uneven distribution of electronic charge leads to positive and negative poles in a molecule. These poles attract electrostatically. |
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Term
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Definition
| A temporary dipole caused by instantaneous, uneven, electron distribution in a nonpolar molecule. |
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Term
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Definition
| Formed when hydrogen is bonded to oxygen, fluorine, or nitrogen. The hydrogen of one molecule becomes attracted to the more electronegative element of the other molecule. These intermolecular attractions cause higher boiling points than predicted. |
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Term
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Definition
| Atoms tend to gain or lose outer shell electrons in order to achieve a noble gas configuration of eight electrons. |
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Term
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Definition
| Two pairs of electrons are shared. |
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Term
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Definition
| Three pairs of electrons are shared. |
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Term
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Definition
| Where there is more than one possible bonding structure in a molecule |
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Term
| Hybrid Orbitals (three types) |
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Definition
| Where two or more pure atomic orbitals are mixed to form identical hybrid orbitals: sp, sp2, sp3 |
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Term
| List the hybrid orbitals present in BF3 and the bond angles. |
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Definition
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Term
| List the hybrid orbitals present in BeF2 and the bond angles. |
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Definition
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Term
| Describe hybrid bonding in: water |
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Definition
| sp3 bonding resulting in a tetrahedron shape with bond angle less than 109.5 degrees. |
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Term
| Describe hybrid bonding in: ammonia |
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Definition
| sp3 bonding resulting in a tetra hedron shape with bond angle less than 109.5 degrees |
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Term
| Describe hybrid bonding in: methane |
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Definition
| sp3 bonding resulting in a tetrahedron shape with bond angle of 109.5 degrees |
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Term
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Definition
| Present between any two orbitals except when two p orbitals share electrons. |
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Term
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Definition
| When two p orbitals share electrons. |
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Term
| Properties of Ionic substances |
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Definition
solids at 25° C
non-conducting as solids
conducting as aqueous solutions or liquids
high melting point
high boiling point
brittle
low volatilities |
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Term
| Properties of Molecular substances |
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Definition
non-conducting as liquids and solids
volatile liquids and solids
many are gases at 25° C
low melting point
low boiling point
soft and waxy solids |
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