Chapter 1 General Chemistry Review Flashcards
define organic chemistry
chemistry of compounds containing carbon
define inorganic chemistry
chemistry of compounds containing metals
define organometallic chemistry
chemistry of compounds containing carbon and metals
organic chemistry studies the distribution and motion of what?
electrons
how do electrons move?
from negative regions (areas of electron density) to positive regions (areas of electron deficiency)
what can block electron flow, and what does this mean?
electron flow can be blocked by large groups, so shape and size of a molecule is important
what happens when electrons move?
a chemical reaction
what do reaction mechanisms represent?
how electrons are thought to flow in a chemical reaction
describe an important aspect (+ and -) of a reaction mechanism
negative charges (high electron density) attack positive charges (low electron density)
what 3 things must be considered to understand the structure of organic compounds?
- what atoms does the molecule contain?
- how are the atoms connected?
- what types of bonds connect the atoms?
by what two things are compounds defined?
- type and number of atoms (molecular formula)
2. how those atoms are connected to each other (connectivity/constitution)
define constitutional isomers
possess the same type and number (molcular formular) of atoms but are connected DIFFERENTLY
give the 2 steps for determining a constitutional isomer
- check MF, if same keep going, if not same, not constitutional isomers
- check connectivity, must be different
from what three things do the properties of an organic compound arise?
- the atoms they contain
- how they are connected
- the type of bonds contained
what does different connectivity give constitutional isomers?
different chemical and physical properties
what holds atoms together in molecules?
chemical bonds
what do an atom’s properties determine?
its bonding
elements are defined by the number of?
protons
what is the atomic number (Z)?
number of protons
what is mass number (A)?
number of protons plus number of neutrons
describe protons and neutrons in a neutral atom
same amount of each
for an uncharged atom, what does the number of electrons equal?
the number of protons
where do electrons reside in atoms?
in atomic orbitals
how many atomic orbitals are there? list them
4: s, p, d, f
what two things are atomic orbitals defined by?
quantum mechanics and Schrodinger wave equation
what 2 properties do electrons exhibit?
particle and wavelike
define atomic orbital
region of space that can be occupied by electron density
what is an occupied atomic orbital compared to?
a “cloud” of electron density
what are the shapes of atomic orbitals?
s, p, d, f
what does the shape of an atomic orbital represent?
the region of space that contains 90-95% of the electron density
what are phases of waves?
regions of positive and negative amplitude
can a wave or electron ever be in the middle of amplitude?
no, only positive or negative
what is the region in the middle of the wave (and amplitude) called?
node
describe the regions of an electron orbital in its wavelike property
have postive and negative regions (phases) and nodes
describe the node of an atomic orbital?
where there is zero probability of finding an electron, or zero electron density
what do electron configurations list?
the orbitals containing electrons and the number of electrons in each orbital
define core electrons
all electrons in completely filled inner energy shells (lower energy)
define valence electrons
electrons in highest energy outer shell (higher energy = REACTIVE)
when are atoms most stable?
when they have a full valence shell
what is a full valence shell also referred to as?
a noble gas configuration
what are noble gases stable (unreactive)?
they have a full valence shell
how do second row atoms (C, N, O, F) achieve a full valence shell?
by obtaining an OCTET of electrons by forming bonds
what is an atomic energy diagram?
when an electron configuration is drawn to show relative energies of the filled or empty orbitals
what are individual atomic orbitals within the same orbital subshell called? what does that mean?
degenerate, same energy
list the 7 steps for drawing an atomic energy diagram
- draw a line to represent orbitals
- lower energy orbitals are drawn at the bottom, higher energy orbitals are drawn at the top
- use periodic tabe to determine which orbitals to draw
- orbitals in the same subshell (3 p or 5 d) are degenerate
- Aufbau principle
- Pauli exclusion principle
- Hund’s rule
define the Aufbau principle
fill lowest energy orbitals first, then proceed to higher energy orbitals
define Pauli’s exclusion principle
each orbital can contain 2 electrons which must have opposite spin (spin up or down)
define Hund’s rule
for degenerate orbitals one electron is placed in each orbital before electrons are paired (minimizes repulsion of electrons giving lower energy arrangement)
define a chemical bond
shared electron pair between two atoms
what does sharing a pair of electrons allow each atom in the bond to do?
gain an additional electron
why do atoms form chemical bonds?
to achieve a full valence shell
what does achieving a full valence shell do to an atom?
stabilizes it
how does hydrogen acieve a full valence shell and why?
with only 2 electrons with only 2 electrons since it has only the 1s orbital
define covalent bond
each atom donates 1 electron and the 2 atoms share the electron pair, each atom obtains a full valence shell!
define ionic bond
attraction between 2 oppositely charged ions. one atom possesses both electrons in the pair
considering Hydrogens electron configuration (1s1) how many bonds is it expected to form?
one bond