Week 1 Flashcards
Atomic # or Z
number of protons (retrieve from periodic table)
Mass #
N + Z (neutrons + protons)
isotopes
same # of protons but different # neutrons
alkali metals
group 1 - basic, react with H2O - explosive, exothermic and more reactive as you move down the group
alkaline earth metals
group 2 - basic, but not as reactive as alkaline metals
noble gases
group 8 - full octet, not very reactive
halogens
group 7 - single electron acceptor
transition metals
form bright colored compounds, i.e. copper = green/blue
exceptions to noble gas configurations
Cr, Mo, Cu, Ag, Au (because more stable if shells are half full or full)
s,p,d,f orbitals
s = 2e, p= 6e, d = 10e, f = 14e
paramagnetic
attracted to magnetic field (unpaired electrons)
diamagnetic
slight deflection of magnetic field (all electrons are paired)
*remember electrons like to fill each shell across before pairing up
Quantum #: n
principal - shell - [1….infinity]
Quantum #: l
azimuthal - subshell (type of orbital) - [0…(n-1)]
s = 0, p =1, d=2, f=3
Quantum #ml
magnetic - specific orbital (orientation in space), [-l…+l]
i.e. if l =2; [-2,-1,0,1,2] (typical d orbital has 5 orbitals)
Quantum #: ms
up or down - spin - (-1/2) or (+1/2)
Quantum # format
[n, l, ml, ms]
What forces hold the nucleus together?
strong nuclear force or nuclear binding energy
nuclear symbols
alpha (same as He), p (proton), n (neutron), beta (electron or positron), gamma (gamma ray light)
Stable Nucleus features
- even # protons and/or neutrons
- N/Z ratio ~ 1 for Z= 20 (up to Ca)
- daughter (product) of parent nuclear rxn is more stable due to release in energy
Alpha decay
reduces mass # of large nuclei (Z>83) - product = 4/2 alpha (like helium but not electrons)
Beta (-) decay/emmission
converts neutrons to protons (occurs when N/Z ratio is too high) product = electron or 0/-1 beta
beta (+) decay (positron emmission)
converts proton to neutrons (occurs when N/Z ratio is too low) product = 0/+1 beta
electron capture
converts protons to neutrons (occurs when N/Z ratio is too low) (reactant side = 0/-1 electron)
gamma decay
product is a photon (emitted when coming from excited state to ground state)
Most stable nucleus
iron-56 (56-Fe) —atoms closer to this is more likely to be more stable
Periodic Trends
- Atomic radius - down + left of the table; radius gets bigger because z(eff) is smaller
z(eff) = # of protons - shielding/core electrons - Ionic Radius - cations are usually smaller because they lose electrons, anions gain electrons and protons can’t hold as close
- non metals form anions
- metals form cations
- 1st ionization energy = energy req’d to remove 1 e-
(trend is opposite of atomic radius – up and right harder to remove e-)
*big jumps in ionization energy indicates all valence electrons have been removed and moving into core electrons
**EXCEPTIONS: Be + B and N + O
These are slightly lower because filled/half-filled (making them more stable (Be over B and N over O) - Electron affinity - energy in gaining an electron (exothermic) - increasing trend from left to right (no vertical trend, but 3rd row is more negative than others - Cl)
* **EXCEPTIONS: groups in Be, N, noble gases (endothermic due to filled shell/half-filled shell - Electronegativity - associated with sharing an electron (shows how close it can pull a shared e- in a covalent bond)
Trend: up and to the right (fluorine)
Q: which is most polar? look for most electronegative atom
Covalent bond
non metal with non metal (covalent network solids - diamond) or molecular compounds (low mp/bp)
Ionic bond
metal with non metal (crystalline, high mp/bp)
Metallic
metal with metal
- conductive (electric + thermal)
- ductile (draw them into wires)
- malleable (pound them to sheets)
- Luster (shiney)
Lewis base
ligand, anything with lone pair of e-
Lewis acid
usually a metal ion