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Chapters 7&8
N/A
60
Chemistry
10th Grade
03/04/2009

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Term
How do you find the amount of valence electrons in an atom?
Definition
Look at the group number
Term
Atoms of which elements tend to gain electrons? Atoms of which elements tend to loose electrons?
Definition
Metals tend to gain elements. Nonmetals tend to loose
Term
How are cations formed?
Definition
An atoms loss of valence electrons forms a cation
Term
How are anions formend?
Definition
The gain of negitively charged electrons by a neutral atom
Term
Valence electrons
Definition
The electrons in the highest occupied energy level of an element's atoms
Term
Electron dot structures
Definition
Diagrams that show valence electrons as dots.
Term
Octect Rule
Definition
Atoms of metals tend to lose their valence electrons, leaving a complete octet in the next lowest energy level. Atoms of some nonmetals tend to gain electrons or to share electrons with another nonmetal to achieve a complete octet.
Term
Halide Ions
Definition
Ions that are produced when atoms of chlorine and other halogens gain electrons
Term
What is the electrical charge of an ionic compound?
Definition
Electrically neutral
Term
What are three properties of ionic compounds?
Definition
-Crystaline structures at room temp
-Have high melting points
-Can conduct electricty when melted or in water
Term
Ionic Compounds
Definition
Compounds composed of cations an anions.
Term
Ionic Bonds
Definition
The electrostatic forces holding ions together in ionic compounds
Term
Formula Unit
Definition
Lowest whole number ratio of ions in an ionic compound
Term
Coordination Number
Definition
the number of ions of opposite charge that surround the ion in a crystal.
Term
How can you model the valence electrons of metal atoms?
Definition
As a sea of electrons
Term
How are metal ions arranged?
Definition
In very compact and orderly patterns.
Term
Why are alloys important?
Definition
Their properties are often superior to those of their component elements
Term
Alloys
Definition
Mixtures composed of two or more elements, at least one of which is a metal.
Term
Metallic Bonds
Definition
Consist of the attraction of the free-floating valence electrons for the positively charged metal ions.
Term
How are the melting points and boiling points of molecular compounds different from those of ionic compounds?
Definition
Molecular compounds tend to have relatively lower melting and boiling points than ionic compounds
Term
What information does a molecular formula provide?
Definition
A molecular formula shows how many atoms of each element a molecule contains.
Term
Covalent Bond
Definition
Atoms held together by sharing electrons
Term
Molecule
Definition
Neutral group of atoms joined together by covalent bonds
Term
Diatomic Molecule
Definition
Molecule consisting of two atoms
Term
What is the result of electron sharing in covalent bonds?
Definition
In covalent bonds, electron sharing usually occurs so that atoms attain the electron configurations of noble gases.
Term
How do electron dot structures represent shared electrons?
Definition
An electron dot structure such as H:H represents the shared pair of electrons of the covalent bond by two dots.
Term
How are coordinate covalent bonds different from other covalent bonds?
Definition
In a coordinate covalent bond, the shared electron pair comes from one of the bonding atoms.
Term
How is the strength of a covalent bond related to its bond dissociation energy?
Definition
A large bond dissociation energy corresponds to a strong covalent bond.
Term
How are oxygen atoms bonded in ozone?
Definition
A hybrid, or mixture, of the extremes represented by the resonance forms
Term
What are some exceptions to the octet rule?
Definition
The octet rule cannot be satisfied in molecules whose total number of valence electrons is an odd number. There are also molecules in which an atom has fewer, or more, than a complete octet of valence electrons.
Term
Single Covalent Bond
Definition
Two atoms held together by sharing a pair of electrons.
Term
Structual Formula
Definition
Represents the covalent bonds by dashes and shows the arrangement of covalently bonded atoms.
Term
Unshared Pair
Definition
A pair of valence electrons that are not shared by atoms
Term
Double Covalent Bond
Definition
A bond that involves two shared pairs of electrons.
Term
Coordinate Covalent Bond
Definition
A covalent bond in which one atom contributes both bonding electrons.
Term
Bond Disassociation Energy
Definition
The energy required to break the bond between two covalently bonded atoms.
Term
Resonance Structure
Definition
A structure that occurs when it is possible to draw two or more valid electron dot structures that have the same number of electron pairs for a molecule or ion.
Term
How are atomic and molecular orbitals related?
Definition
Just as an atomic orbital belongs to a particular atom, a molecular orbital belongs to a molecule as a whole.
Term
How does VSEPR theory help predict the shapes of molecules?
Definition
According to VSEPR theory, the repulsion between electron pairs causes molecular shapes to adjust so that the valence-electron pairs stay as far apart as possible.
Term
In what ways is orbital hybridization useful in describing molecules?
Definition
In what ways is orbital hybridization useful in describing molecules?
Term
Molecular Orbitals
Definition
When two atoms combine, this model assumes that their atomic orbitals overlap
Term
Bonding Orbitals
Definition
A molecular orbital that can be occupied by two electrons of a covalent bond
Term
Sigma Bond
Definition
When two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting two atomic nuclei.
Term
Pi Bond
Definition
The bonding electrons are most likely to be found in sausage-shaped regions above and below the bond axis of the bonded atoms.
Term
Tetrahedral Angle
Definition
In this arrangement, all of the H—C—H angles are 109.5°.
Term
Hybridization
Definition
Several atomic orbitals mix to form the same total number of equivalent hybrid orbitals
Term
How do electronegativity values determine the charge distribution in a polar bond?
Definition
The more electronegative atom attracts electrons more strongly and gains a slightly negative charge. The less electronegative atom has a slightly positive charge.
Term
What happens to polar molecules between a pair of oppositely charged metal plates.
Definition
When polar molecules are placed between oppositely charged plates, they tend to become oriented with respect to the positive and negative plates.
Term
How do intermolecular attractions compare with ionic and covalent bonds?
Definition
Intermolecular attractions are weaker than either ionic or covalent bonds.
Term
Why do network solids have high melting points?
Definition
Melting a network solid would require breaking covalent bonds throughout the solid
Term
Why do network solids have high melting points?
Definition
Melting a network solid would require breaking covalent bonds throughout the solid
Term
Nonpolar Covalent Bond
Definition
When the atoms in the bond pull equally (as occurs when identical atoms are bonded), the bonding electrons are shared equally
Term
Polar Covalent Bond
Definition
Covalent bond between atoms in which the electrons are shared unequally.
Term
Polar Molecule
Definition
One end of the molecule is slightly negative and the other end is slightly positive.
Term
Dipole
Definition
A molecule that has two poles is called a dipolar molecule.
Term
van der Waals Forces
Definition
The two weakest attractions between molecules.
Term
Dipole Interactions
Definition
Occur when polar molecules are attracted to one another.
Term
Dispersion
Definition
The weakest of all molecular interactions, are caused by the motion of electrons.
Term
Hydrogen Bonds
Definition
Attractive forces in which a hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom.
Term
Network Solid
Definition
Solids in which all of the atoms are covalently bonded to each other.
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