Chemistry 2 test
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Chemistry 2 test
Chemistry 2 test
Difference between atoms and ions
Atoms are a singular unit. when it has a charge it becomes an ion.
an atom can be an ion, but not all ions are atoms.
when an atoms outermost orbital gains or loses an electron, it becomes an ion.
difference between molecules and polyatomics
The difference between regular molecules and polyatomic ions is that polyatomic ions have a charge on the entire molecule as a whole.
difference between covalent and ionic bonds
: results from two atoms
electrons usually between two non metals
: electrostatic attraction between charged particles after a complete transfer of electrons from one atom to another. usually between non metal and a metal.
what substances occur as a diatomic molecule? (7)
H2, N2, O2, F2, Cl2, Br2, and I2
C2 O 2-/4
what elements tend to gain electrons and form _____?
Non metals; anions
What elements tend to lose electrons and form ____?
what is the definition of the ground state electron configuration for atoms?
lowest energy configuration
What are the relative size trends?
across a period- radius increases
Down a column- radius gets smaller
(biggest at bottom left, smallest at upper right)
What are the trends for Ionization energy (Ei)?
across a period, Ei gets greater
down a column, Ei gets smaller
exceptions for group 2A
(greatest at noble gases, lowest at lower left)
what is Ionization energy (Ei)?
the amount of energy necessary to remove the highest energy electron from an isolated neutral atom in the gaseous state
What is electron affinity (Eea)?
the energy that occurs when an electron is added to an atom
What are the trends for electron Affinity?
Highest affinity at halogens (F, Cl, Br, I, At) because greatest E lost.
greater going right.
what does it mean when Eea=0?
energy is required but amount is NOT known
What is the octet rule?
lowest energy orbitals fill first
Noble gas configurations.
Na: [Ne] 3s1
Na(s)--> Na(g) +E change
1/2 Cl2--> Cl(g) +E change
Na(g)--> Na+(g) +e- +E change
Cl(g)+e- -->Cl-(g) -E change
Na+(g)+Cl-(g)-->NaClg -E change
overall reaction is negative, favorable.
What are lattice energies? (U)
the amount of energy required to break up an ionic solid to individual gasous atoms.
trends of lattice method
as radii goes up, the easier it is to break the bonds of electrons
as charge goes up (ex. 2+, 3+) the U goes up
Molecule vs. Compound
: a unit of matter held together by covalent bonds
: a pure chemical substance consisting of 2 or more elements
electronegativity and relation to types of bonds
e-negativity >1.7 ionic bonds
e-negativity=.4-1.7 polar covalent
e-negativity <.4 nonpolar covalent bond
across a row
: electronegativity increases
down a column
: electronegativity decreases
electronegativity's relation to Ei and Eea
as Ei goes up, e-neg goes down
as Eea goes up, e-neg goes up
what is a lewis dot structure?
a representation of an atoms valence e-, by using dots. the placement of the dots is related to the e- are located.
what are resonance structures? what are the rules?
same connectivity, different arrangements of electrons
minimize formal charges to make equal. 0>1>2
charges on more electronegative atoms are best
S=C=N- is better than S-=C=N
lewis structure for sulfate
Lewis structure for ammonium
Lewis structure for acetate
lewis structure for cyanide
lewis structure for hydroxide
lewis structure for nitrate
lewis structure for carbonate
lewis structure for phosphate
lewis structure for oxalate
valence shell electron pair repulsion
bonds are an area with a high concentration of negative charge. negative charges repel eachother and bonds want to be as far away from one another.
what is the geometric and molecular shape of a molecule with a charge cloud of 2?
Linear for both
what is the geometric and molecular shape of a molecule with a charge cloud of 3?
Trigonal Planar for both
what is the geometric and molecular shape of a molecule with a charge cloud of 4 with no lone pairs?
Tetrahedral for both
what is the geometric and molecular shape of a molecule with a charge cloud of 4 with one lone pair?
Tetrahedral for e-
trigonal pyramidal for molecular geo
what is the geometric and molecular shape of a molecule with a charge cloud of 4 with two lone pairs.
Tetrahedral for E- geo
Bent for molecular geo.
Sigma and Pi bond definition
: overlap of singular e-
: sideways bond overlap above/below Sigma bond.
Octohedral bonds are made with __ electron pairs
square pyramidal geometry is made with __ electron pairs
what molecules do not need a full octet?
Aluminum and Boron only need 3
describe the formation of sp3hybrid orbitals and identify which atoms use sp3hybridization to form bonds
single bonded atoms (i.e. CH4)
describe the formation of sp2hybrid orbitals and identify which atoms use sp2hybridization to form bonds
Double bonded atoms (i.e. C2H2)
describe the formation of sp hybrid orbitals and identify which atoms use sp hybridization to form bonds
triple bonded atoms (i.e. C2H2)