Class 1 Flashcards
prefix - nano
10-9
prefix - micro
10-6
prefix - mili
10-3
prefix - centi
10-2
prefix - kilo
103
prefix - mega
106
angstrom
unit of length
10-10 m
density formula
mass / volume
kg/m3 or g/cm3
density of water
1 g/cm3
empirical formula
reducing the molecular formula to the smallest possible ratio
ammonium
NH4+
hydronium
H3O+
acetate
CH3CO2-
bicarbonate
HCO3-
cyanide
CN-
hydroxide
OH-
nitrate
NO3-
nitrite
NO2-
perchlorate
ClO4-
carbonate
CO32-
sulfate
SO42-
sulfite
SO32-
phosphate
PO43-
what is a mole
6.02 x 1023 entities (Avogadro’s number)
how to calculate the # of moles
mass in grams / molecular weight
what is molarity
of moles of solute / # litres of solution
Law of Conservation of Mass
amount of mass does not change in a chemical reaction
limiting reagent
limits how much product a reaction can produce
group 1 metals oxidation state
+1
group 2 metals oxidation state
+2
fluorine oxidation state
-1
hydrogen oxidation states
+1 when bonded to something more electroneg. than carbon
-1 when bonded to something less electroneg. than carbon
0 when bonded to carbon
oxygen oxidation state
-2
oxygen’s oxidation state exception in peroxides
-1 instead of -2
what never assumes a neg oxidation state
metals
what does a central nucleus contain
protons and neutrons (aka nucleons)
how are electrons held in the atom
by the electrostatic attraction of the positively charged nucleus
what is the atomic number
of protons in the nucleus of an atom
what is the atomic mass number
of neutrons + # of protons
what is an isotope
two atoms of the same element with a different # of neutrons
what is the atomic weight of an element
a weighted average of the masses of the element’s isotopes
strong nuclear force
holds the protons + neutrons together in a nucleus
unstable nuclei are..
radioactive
radioactive decay
alternating the # of protons/neutrons or lowering of energy
alpha particle
2 neutrons + 2 protons
emitted from parent nucleus
types of beta decay
beta -
beta +
electron capture
characteristic of beta decay
conversion of a neutron into a proton
are beta or alpha particles more dangerous
beta - smaller + have more energy
beta - decay
too many neutrons: conversion of a neutron into a proton - ejected from the nucleus
atomic number is now 1 greater
mass number remains the same
which is the most common type of beta decay
beta -
beta + decay
too few neutrons: conversion of a proton → neutron and a positron
atomic number is now 1 less
mass number is the same
positron vs electron
positron is the electron’s antiparticle
identical to electron but with a positive charge
electron capture
increase # of neutrons by capturing an electron from the closest electron shell & uses it to convert a proton into a neutron
atomic number is now 1 less
mass number is the same
gamma decay
when a nucleus relaxes to its ground state, it emits photons of electromagnetic radiation (aka gamma photons)
characteristics of gamma photons
very high frequency and energy
no mass or share
ejection from nucleus doesn’t change the atomic number or mass number
half life equation
nuclear binding energy
energy that was released when the nucleons were bound together (by the strong force to form nucleus)
the greater the binding energy per nucleon..
the more stable the nucleus is
mass defect
when nucleons bind to form the nucleus, some mass is converted to energy so the mass of the combined nucleus is less than the sum of the nucleons masses
for a stable nucleus, the mass defect will always be..
positive
mass defect =
total mass of separate nucleons - mass of nucleus
Einstein & nuclear binding energy formula
energy of photon formula
absorption of a photon - energy change
positive energy change
emission of a photon - energy change
negative energy change
limitation of Bohr’s model
only applies to atoms with only one electron
what is an orbital
a 3D region around the nucleus where electrons are most likely to be found
s subshell
one spherical orbital
p subshell
3 dumbbell shaped orbitals
Aufbau’s principle
electrons occupy the lowest energy orbitals available
sub shells are filled in order of increasing energy
Hund’s rule
electrons in the same subshell occupy available orbitals before pairing up
Pauli exclusion principle
no more than 2 electrons in any orbital
diamagnetic
an atom that has all of its electrons spin paired
no net magnetic field → will be repelled by a produced magnetic field
paramagnetic
when an atom’s electrons are not all spin paired
attracted to externally produced magnetic fields
isoelectronic
when 2 atoms have the same electron configuration
atomic radius pattern
decreases across a period
increases down a group
ionic radius pattern
radius decreases as electrons are removed (cation)
radius increases as electrons are added (anion)
what is ionization energy
energy needed to remove an electron from an atom
ionization energy pattern
increases across a period
decreases down a group
what is electron affinity
amount of energy released when an electron is added
electron affinity pattern
electron affinity becomes more negative as we move across a period and up a row (except noble gases)
what is electronegativity
tendency for an atom to attract electrons
electronegativity pattern
increases across a period
decreases down a group
order of electronegativity
uncle F O N Cl
Br I S C H
what is acidity (trend)
how well a compound donates protons/excepts electrons
acidity pattern
increases across a period
increases down a group
number of protons =
atomic number
number of neutrons =
atomic mass - atomic number
Planck’s constant
6.6 x 10-34 J.s
speed of light = c
3 x 108
