Big Idea #1: Atoms, Elements, and Building Blocks of Matter
measurement of single atom electrons
1 eV= 1.6 • 10^-19 Joules.
all energy levels
1 s, 2 s p, 3 s p d, 4 s p d f
period trends have 3 basic rules
1. electrons attracted to protons a. closer to nucleus = stronger attraction b. more protons = stronger attraction. 2. electrons are repelled by each other so if other electrons are btwn valence electrons and nucleus the valence will b less attracted to nucleus this is shielding. 3. completed shells are very stable and atoms will + or - valence electrons to create complete shell for charge of 0
1 mole of carbon atoms has mass of
12 g/mol = 12 amu
electron configuration for nickel
1s22s^22p^63s^23p^63d^84s^2
determine electron configuration of sulfur
1s^22s^22p^63p^63s^23p^4
p subsehll energy level compared to s subshell
3 times higher because more electrons in subshell
1 mole =
6.02 x 10^23
frequency and wavelength relationship with energy
E=frequency/wavelength. inversely proportional. higher freq = more energy
Energy and Electromagnetic Radiation relationship
E=hv e=energy change, h=planck's constant, v=frequency
PV=nRT labeled
P= pressure (atm), V= volume (L), T=temp (K), R= gas constant .0821 (L•atm/mol•K)
ideal gas law with moles
PV=nRT
[Ar]4s^23d^6 lose 2 electrons
[Ar]3d^6
shorthand electron configuration example
[Xe] 6s2 4f14 5d10
second ionization energy
after first ionization energy electrons has been remove so atom becomes + charged ion so energy require to remove next electron
coulomb's law
amount of energy electron has depends on distance from nucleus
ionization energy
amount of energy needed to remove electron
Photoelectron Spectroscopy (PES)
amount of ionization energy 4 all electrons ejected from nucleus
move to the right periodic table
atomic radius deceases, ionization energy increases, electronegativity increases
when moving from left to right across period what happens to atomic radius?
atomic radius decreases because protons are added to nucleus so valence electrons are more strongly attracted resulting in decrease in atomic radius. if electrons added in same shell same dis from nucleus there is not much shielding effect bc not in Dif levels
when moving down a group what happens to atomic radius?
atomic radius increases because moving down a group shells of electrons are added so each shell shield more distant shells from nucleus and valence electrons get farther away. protons are being added but the shielding effect is too negatively charged and cancels out added positive charge
moving down periodic table
atomic radius increases, ionization energy decreases and electronegativity decreases
ion
atoms which gain or lose electron
molar mass
avg mass 4 1 mole
what happens to binding energy in PES graph
binding energy (ionization energy) decreases from left to right
incoming radiation energy
binding energy + kinetic energy
charge of elements in CuBr2
bromide: +1 (2) = +2 copper: -2
frequency wavelength and spd of light
c=wavelength•frequency c=m/s, wavelength= m, frequency 1/s or Hz
what type of ion are transition metals
cation
electron configuration
complete description of energy level and subshell
dalton ideas
compounds always contain same ratio of elements and never atoms are created or destroyed in chem ratio
molarity
concentration of solution
third subshell
d holds 10 electrons
what happens to metallic characteristics of elements as go right on pt
decrease
when moving down a group what happens to electronegatively?
decrease because more shielding
when moving down a group. what happens to ionization energy?
decreases because shells of electrons added so more shielding which reduces pull of nucleus making it easier to remove electron with less energy
subshells
describe shape of space can b found
relative height of peaks
determine number of electrons in subshell
what do PES peaks represent
different energy level. # of peaks shows us not all electrons at n=2+ are located same distance from nucleus.
atomic radius
distance from nucleus to valence electrons
why anions are larger than atoms?
electrons are being added to atoms so electron-electron repulsion increases causing valence electrons to move farther apart which increases the atomic radius
why are cation smaller than atoms?
electrons are being removing so outer shell is lost making cation a smaller atom. also electrons are removing and electron-electron repulsion is reduced allowing all electrons to move closer to nucleus
quantized
electrons can exist only at specific energy levels
give off energy from electromagnetic radiation
electrons drop from higher to lower energy levels
absorb energy from electromagnetic radiation
electrons jump 2 higher energy levels.
metalloids
elements that borderline between metals and nonmetals
periods represent what?
energy level
fourth subshell
f holds 14 electrons
electrons do not have specific orbits. what do they do?
function in region of space
distance from nucleus and amount of kinetic energy electron has
further away from nucleus require less energy to remove therefore it will move faster
moles
g/Mm
when close to full energy level
gain electron to achieve stability
Coulomb's law qualitatively applied
greater charge of nucleus, the more energy an electron with have. coulomb potential energy for 1s electrons is lower (more negative) than 3s electrons. amount of energy required to remove 1s electrons is greater than amount need to remove 3s bc farther from nucleus so less attration
vertical
groups
s block elements
groups 1 and 2 + helium
p-block elements
groups 13-18
electronegatively trends exceptions
helium, neon, argon don't form bonds but larger noble gases do and follow general trends
what can we examine with speed of ejected electron
how far away they were from nucleus
electronegativity
how strongly nucleus of atom attracts electrons of other atoms in a bond
what happens to electrons potential energy as distance increases from nucleus
increase bc less force from nucleus so more PE to separate from nucleus or bind
why second ionization energy is greater than first ionization energy?
increases because electron removed so electron-electron repulsion decreases and valence electrons move closer to nucleus this increases attractive force between electrons therefore increasing needed ionization energy to remove next electron
when moving from left to right across period what happens to electronegativity?
increases because increase in nuclear charge
when moving from left to right across period what happens to ionization energy?
increases because protons are added to nucleus which increases positive charge. because of this negatively charged valence electrons are more sternly attracted to nucleus which increases energy required to remove them.
f block elements
inner transition metals
moles of atoms for binding energy
kJ/mol or MJ/mol
closer an energy level is to the atom menas
less energy electrons on that level bc smaller ring
molarity equation
moles of solute/L of solution
STP moles, volume equation
moles= liters/22.4(L/mol)
faster an ejected is going...
more KE it has
anion
more electrons than protons
cation
more protons than electrons
how are electrons found around nucleus
moving around a certain (area) sub shell and energy level (distance) away from nucleus
how to calculate percent composition
multiple # of atoms by atomic mass. then find total atomic mass for compound. then divide each element by the total molar mass to find % comp.
all energy of incoming radiation
must be conserved and if doesn't go into break electron free then will be converted into KE
molecular formular
needs molar mass. find molar mass of empirical formula then divide that mass by molar mass given. the answer needs to be multiplied to empirical compound then gives molecular formula
if gain electron
negative ion
atomic number
number of protons
when is most stable configuration from energy standpoint
outermost energy level has 8 electrons (2 in the s and 6 in the p subshell)
valence electrons
outermost s and p subshells
second sub shell
p holds 6
horizontal
periods
lose electron
positive ion
At STP
pressure 1, temp 273 K. can convert directly btwn vol and # of mol bc at STP, 1 mol of gas occupies 22.4 L
binding energy
removal energy of electron and always positive value
shorthand electron configuration
replacing part of configuration w last noble gas that's filled.
first ionization energy
required energy to remove electron
first subshell
s hold 2 electrons
empirical formula
simplest ratio of compound
how to calculate charge of elements in compound
start with metal charge then find gas then multiple by each element by charge to number of element in compound so balance to zero
how to find empirical formula
take grams of each element then divide by element's atomic mass. the one with the smallest moles divide all elements by that amount then gives empirical ratio for compound
molecular formula
the actual formula of a compound
what two factor affect electronegativity
the smaller atom is the more effectively nuclear charge is felt past valence electrons (bc less shielding) and higher electronegatively will be. secondly the closer an element is to having full energy level the more likely ir is to attract necessary electrons
d block elements
transition metals
Pauli Exclusion Principle
two electrons in same orbital cannot have same spin (one clockwise that other counter)
dalton ideas example
water (h2o) always have 2 hydrogen atoms for every 1 oxygen atom
aufbau principle
when building electron configuration electrons re placed in sub shells by increasing energy
hund's rule
when electrons added to subshell always will occupy empty orbital first before pairing up when no empty space
rules for transition metals forming cations
when losing electrons will lose higher-level s electrons before losing any lower level d electrons
as electrons are removed, ionization energy increases gradually until shell is empty, then makes a big jump. why is there a big jump?
when valence shell is empty next electron comes from much closer shell to nucleus making ionization energy for electron much larger
PES graph
y-axis describe relative # of electrons from given energy level. x-axis shows binding energy.
