25.1-25.10 Flashcards
alpha decay
alpha is the biggest (2 protons 2 neutrons)
alpha particle can be stopped by human skin
beta decay (three types)
proton to neutron (vice versa)
Beta-
Beta+
Electron capture
stronger than Alpha particle, but can be stopped by aluminum foil
Beta- decay (Standard BETA decay)
unstable nucleus has TOO MANY NEUTRONS
converts neutron to proton and electron
atomic number UP by 1, mass stays the same
Ca -> Sc + 0 -1 beta
what is emitted?
Beta+ decay (positron emission)
too few neutrons
proton becomes a neutron and a positron (identical to electron but with a positive charge)
atomic number DOWN by 1, no change in atomic mass
Co -> Fe + 0 +1 beta
electron capture
converts a proton into a neutron by capturing an electron
no change in mass number, but atomic number DOWN by 1
gamma decay
often accompanies other kinds of decay
stopped by lead or concrete
“gamma lead”
nuclear bind mass
LOSES mass when nucleus is formed
kilograms in an amu
1.66 ( 10^-27) kg
equation for nuclear binding energy
deltaMass (in amu) * 931.5 MeV
equation for energy of photon
E = hf
“Photons just wanna Have Fun”
fun is speed of c / wavelength
Planck’s constant
6.63 * 10^-34
electron has more energy when farther from nucleus!
like potential energy
En = (-2.178 * 10^-18) / n^2
Change in energy = E_final (n=1) - E_starting (n=2,3)
negative means energy is RELEASED
Bohr model contains 1 electron
1 ELECTRON = BOHRING
the p orbitals are like dumbbells
3 x,y,z
d has 5 orbital configurations (p has 3)
f has 7 orbital
diamagnetism/paramagnetism
diamagnetism - all electrons are spin paired
REPELLED by externally produced magnetic field
paramagnetism - not all spin paired (“WEIRDLY uneven”)
attracted into externally produced magnetic fields
PERIOD and GROUP (and block)
PERIOD HORIZONTALLY (periods are like elipses…)
GROUP VERTICALLY (groups are like columns, stacks)
there are 4 blocks (s, p, d, f)
subtract 1 for d from period
subtract 2 for f from period
3d
subtract down 1
4s2 3d10 …
THE FIRST D ROW IS ACTUALLY 3
EXCEPTIONS: Chromium and Copper electron configuration
FILL the d orbitals (4->5, 9->10)
EXCEPTIONS: Ag and Au
9->10
Ag = silver
Au = gold
FILL the d orbitals
isoelectronic
iso = same electric shape
F- and Neon (same e- configurations)
Transition metals lose s electrons before they lose d electrons
IMPORTANT - the s is valence electron since n > n-1
Transition metals are elements in the d block
ex. Ti is [Ar] 4s2 3d2
Ti2+ is [Ar] 3d2
first two groups
Alkali metals (1 word) Alkaline earth metals (2 words)
halogens are powerful oxidizing agents
x
Metalloids
B Si Ge As Sb Te Po
atomic radius DECREASES going left to right (Zeff is higher to the right)
also decreases going up
X+ < X < X-
cations are smaller than anions
ionization energy = energy to remove an electron
INCREASES going right – valence electrons are more tightly bound
the 2nd ionization energy is always more than the 1st
electron affinity
halogens are VERY affinitive (energy is released = negative, increased stability)
Very POSITIVE for noble gases and ALKALINE EARTH METALS because they need a new level or sublevel and this destabilizes (“they really don’t want more electrons”)
affinities increase going RIGHT and UP (a general trend, does not include noble gases)
electronegativity
pulls electrons when forming a covalent bond (unfair sharing)
F > O > N/Cl > Br > I > S > C/H
formal charge
valence electrons - 1/2 (electrons in bonds) - lone electrons
resonance structures
nonbonding electrons, double and triple bonds can move around
coordinate covalent bond
lone pair forms a bond on its own (obtains a formal positive charge) = LEWIS BASE
LEWIS BASE = NUCELOPHILE
LEWIS ACID = ELECTROPHILE = accepts electrons
coordinate covalent bond
lone pair forms a bond on its own (obtains a formal positive charge) = LEWIS BASE
LEWIS BASE = NUCLEOPHILE
LEWIS ACID = ELECTROPHILE = accepts electrons
oxidation states p. 668
keep working on it
