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21 Cards in this Set
- Front
- Back
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paramagnetic
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atoms or ions with unpaired electrons. they are attracted to a magnetic field
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Atomic Radii
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-INCREASE going down a group
-DECREASE going across a period |
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Ionization Energy
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the energy needed to remove an e- from an atom in the gas phase.
*always positive* -DECREASES going a down a group -INCREASES across a period |
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Electron Affinity
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The energy change in which an e- is acquired in the gas phase.
*always negative* -LESS negative down a group -MORE negative across a period |
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Ionic Radii for Cations
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Cations have smaller radii than their neutral atoms.
-INCREASES going down groups IA, 2A & 3A -DECREASES across a family to 3A |
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Ionic Radii for Anions
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Anions have larger radii than their neutral atoms.
-INCREASES going down groups 6A & 7A |
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Valence Electrons
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The e- involved in chemical bonds & reactions. They determine the elements chemical properties.
-For s & p block valence e- = group # -For transitional metals valence e- = group # + ns e- + (n-1)d e- |
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Ionic Bond
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forms when one or more e- are transferred from one atom to another.
-usually metals & nonmetals |
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Covalent Bond
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Involves the sharing of e- between atoms.
-usually nonmetals. |
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Lattice Energy
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The energy change when ions in the gas phase come together to form an ionic bond.
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Lattice Structure
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Ions are arranged in a lattice structure to maximize electrostatic attractions.
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Octet Rule
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The tendency of molecules & polyatomic ions to form structures in which each atom is surrounded by 8 e-.
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Resonance Structures
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Used to represent bonding in a molecule or ion when a single Lewis Structure fails to accurately describe the actual e- structure. The properties of a molecule w/ resonance structures is the average of the properties of the resonance structures. The positions of atoms dont change.
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Incomplete Octets
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BeF2
BF3 BH3 |
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Radicals
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molecules w/ an unpaired e-
NO2 |
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Extended Octet
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Period 3 or higher..
PF5, SF6, XeF4 |
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VSEPR Theory
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Predicts the 3D shapes of molecules. According to VSEPR, bond pairs and lone pairs repel each other and are as far apart as possible.
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Generic Formula
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AXnEm
A = central atom Xn = atoms bonds to A Em = lone pairs on A |
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Formal Charge
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FC = group # - (LPE - 1/2BPE)
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Dipole Moment
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Separation in charge multiplied by the distance of separation
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Bond Dissociation Energy
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-breaking a bond is endothermic
-making a bond is exothermic |
