Module 0 - Essential Review Flashcards
If we assume a gas behaves ideally, what assumptions have we made about the molecules and/or how they behave?
- molecules are small and v far apart
- constant random motion
- collide with each other and walls
- perfectly elastic collisions
- no forces between molecules
- kinetic energy is proportional to kelvin temperature
What is the equation of state for an ideal gas? What is pressure a measure of? What is volume a measure of? What is temperature a measure of?
PV = nRT
P is how hard they hit container edges
V is how much space takes up
T is avg kinetic energy
What is Dalton’s law of partial pressures?
Pressure of all gases added = total pressure
How do atomic radii vary across a period? Down a group?
Down and left increase
How do the radii of X-, X, and X+ compare with each other?
X+ < X < X-
How do the ionization energies vary as we move across the second and third periods?
Up and right increase
How do IEs vary as we move down a group?
Decrease down
What is meant by the term polar covalent?
Not given over like ionic but not in the middle like nonpolar
What is electronegativity a measure of? For the p-block elements, how do ENs vary as we move across a period? Down a group?
How strong they attract electrons
Increase up and right
Describe the nature/structure of (i) an ionic compound, (ii) a molecular compound
(i) lattice, positive and negative charges, solid
(ii) different shapes, can be any state
Which ionic compounds are generally soluble? Which ones are generally insoluble?
- alkali, nitrate, ammonium always soluble
- Cl, Br, I soluble except Pb, Hg, Ag
- SO42- soluble except Ca, Sr, Ba, Ag, Hg, Pb
- CO32-, PO42-, S2- insoluble except previous rules
- OH- insoluble except previous, also slightly soluble with alkaline
What are the basic steps involved in drawing an acceptable Lewis structure for a molecule?
Central atom, add bonds, add lone pairs, check with formal charges
What is the difference between isomeric and resonance structures?
Isomers change atom location, resonance changes electron location
What is meant by formal charge and oxidation state?
FC = valence electrons - # dots - # lines OS = valence electrons - # dots - # lines IF MORE EN
Of what use is the concept of formal charge?
Evaluating Lewis structures
What is the basic premise of VSEPR theory?
Groups arrange themselves around an atom to minimize electron pair repulsions
