Unit 3: Compounds Flashcards
how to draw lewis structure
1) Count all valence electrons
2) Determine the central atom (element that is fewest in number)
3) Draw single bonds between the different atoms in the molecule
4) Put all remaining electrons in as bonds or lone pairs, and try to give each atom an octet
electron donor/ acceptor
An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. … In chemistry, a class of electron acceptors that acquire not just one, but a set of two paired electrons that form a covalent bond with an electron donor molecule, is known as a Lewis acid.
if you have 4 nonboding pairs plus bonds, and 4 bonds plus nonbinding pairs, whats the geometry and arrangement
Geometry: tetrahedral
Arrangement: tetrahedral
if you have a total of 3 nonbinding pairs plus bonds and 3 bonds plus nonbonding pairs, whats the geometry and arrangement?
Geometry: Trigonal Planar
Arrangement: Trigonal Planar
monoatomic ion
A monatomic ion is an ion consisting of a single atom. If an ion contains more than one atom, even if theseatoms are of the same element, it is called a polyatomic ion. For example, calcium carbonate consists of the monatomic ion Ca2+ and the polyatomic ion CO32−.
What are all compounds made of
All compounds are made of more than one element bonded together
resonance
When there is more than one good Lewis structure, we draw ALL Lewis structures and put double headed arrows between them. These are called resonance structures. The weighted average tells us about the actual structure.
The actual structure of a molecule is NOT switching back and forth between different resonance forms. Rather the actual structure is the average of the different resonance forms. All of the electrons in molecules move extremely fast.
non-electrolyte
a substance that does not readily ionize when dissolved or melted and is a poor conductor of electricity.
pauling electronegativity
derived from bond strength. A–B bond is STRONGER than the average of A–A and B–B! Difference is assumed to be “ionic” in nature
if you have a total of 3 nonbinding pairs, but a total of 2 bonds plus 1 nonbonding pair whats the geometry and arrangement?
Geometry: trigonal planar
Arrangement: bent
if you have 4 nonbinding and bonds total, but 1 bond and 3 nonbinding pairs, whats the geometry and arrangement
Geometry: tetrahedral
Arrangement: linear
electrolyte
An electrolyte is a substance that will dissociate into ions in a solution. The ions in the solution give it the capacity to conduct electricity.
just look at the picture
in a covalent what are the electrons shared between both atoms considered to be?
The shared electrons are considered as owned by BOTH atoms! (Both hydrogens now have 2 electrons.)
electronegativity
Electronegativity is the ability of an atom to pull electrons towards itself.
Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used.
A measure of how much an atom wants electrons.
if you have a toatl for 4 nonbinding pairs and bonds, but 2 are bonds and 2 are nonbinding, whats the geometry and arrangement
Geometry: Tetrahedral
Arrangement: bent
whats all the possible arrangements of electron domains if you have 2 nonbonding pairs plus bonds
Nobonding Pairs Plus Bonds:
Number of Bonds plus Nonbinding Pairs: 2
Geometry of Nonbinding Pairs and Bonds bout the Central Atom: linear
Arrangement of the Atoms of the about the central atom: linear
electrostatic force
Coulomb force, also called electrostatic force or Coulomb interaction, attraction or repulsion of particles or objects because of their electric charge.
VSPER?
Valence shell electron pair repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm theory after its two main developers.
polyatomic atoms
A polyatomic ion, also known as a molecular ion, is a charged chemical species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit. The prefix poly- means “many,” in Greek, but even ions of two atoms are commonly referred to as polyatomic.
chemical bond
Chemical bond referrs to the forces holding atoms together to form molecules and solids. This force is of electric nature, and the attraction between electrons of one atom to the nucleus of another atom contribute to what is known as chemical bonds. A chemical bond formed between two ions with opposite charges
disassociation
Dissociation in chemistry and biochemistry is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into smaller particles such as atoms, ions or radicals, usually in a reversible manner.
expanded octet
“Expanded octet” refers to the Lewis structures where the central atom ends up with more than an octet, such as in PCl5 or XeF4. In drawing the Lewis structure for PCl5 , there is a total of 40 valence electrons to put in (5 + 5x7 = 40).
Covalent bond
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
dipole
The polarity of a molecule is measured by its dipole moment. The larger the dipole moment, the stronger the charge separation.
The dipole moment of H2O is 1.85 D, which means water is VERY polar. Large dipole moments are a result of large differences in electronegativity.
formal charge
•How to Assign Formal Charges
–For each atom, count the electrons in lone pairs and half the electrons it shares with other atoms.
–Subtract that from the number of valence electrons for that atom: the difference is its formal charge.
list all characteristics of Ionic Compounds
HIGH melting/boiling points metal (or NH4+) & non-metal conduct electricity atoms gain/lose electrons positive ion = cation negative ion = anion
non-polar covalent bond
Image result for nonpolar covalent bond definition Nonpolar covalent bonds are a type of chemical bond where two atoms share a pair of electrons with each other
crystal lattice
the symmetrical three-dimensional arrangement of atoms inside a crystal.
Crystals are composed of three-dimensional patterns. These patterns consist of atoms or groups of atoms in ordered and symmetrical arrangements which are repeated at regular intervals keeping the same orientation to one another. By replacing each group of atoms by a representative point a crystal lattice is obtained.
octet rule
Atoms with 1, 2, or 3 valence electrons will usually lose them all to become cations.
Atoms with 5, 6, or 7 valence electrons will usually gain electrons in order to give it eight valence electrons.
polar covalent bond
Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms. In a polar covalent bond, the electrons are not equally shared because one atom spends more time with the electrons than the other atom.
list all characteristics of covalent compounds
low melting/boiling points only non-metals (except TiCl4) don’t conduct electricity (except acids and bases) atoms share electrons
Allen EN
Average energy of all the valence electrons. (Can be measured for all elements)
if you have a total of 4 nonbinding pairs plus bonds but 3 bonds and 1 nonbinding and 3 binding, whats the geometry and arrangement
Geometry” tetrahedral
Arrangement: trigonal pyramidal
