Atomic Structure Flashcards
(31 cards)
mass number
sum of protons and neutrons
protium
1 p 0 n
deuterium
1p 1n
tritium
1p 2n
atomic mass
same as mass number. in amu
atomic weight
constant for a given element, reported in periodic table. almost all elements exist as two or more isotopes, usually in same proportions. weighted average. mass of “average” atom of that element, and mass of one mole of the element, in grams.
1 amu
1/12 the mass of carbon-12 atom, so amu is approx mass of one p or n
mass number
sum of protons and neutrons
Avogadro’s number
6.02 x 10^23. a mole is that amount of things. atomic weight of carbon is 12 g/mol, which means average carbon atom has a mass of 12.0 amu, 6.02 x 10^23 carbon atoms have 12 g
Rutherford
atom has dense positively charged nucleus
Planck
E=hf, energy of a quantum, h is a constant
Bohr
just hydrogen atom: central proton, electron in circular orbit
L=mvr and K=1/2mv2
L=nh/2(pi) n is principal quantum number
Bohr’s energy of the electron
E=-Rh/n2
Rh is Rydberg unit of energy.
Applications of Bohr model
photon is emitted when going down in level.
energy is E=hc/lambda (wavelength of radiation)
Lyman series
group of hydrogen emission lines corresponding to transitions rom energy levels greater than 2 to n=1. larger energer transitions than Balmer series, shorter photn wavelengths in UV section
Balmer
group of hydrogen emission lines corresponding to transitions rom energy levels greater than 3 to n=2
Paschen
group of hydrogen emission lines corresponding to transitions rom energy levels greater than 4 to n=3
quantum mechanics
more electrons: not a clearly defined circular pathway at a fixed distance
Heisenberg uncertainty principle
impossible to know both the momentum and position of the electron
principal quantum number
n. diffrence in energey between 2 shells decreased as distance from nucleus increases (E=[1/ninitial2-1/nfinal2])
angular moment/azimuthal quantum number
l. 0 to n-1. so for n=1, l=0. n=2, l=0 and l=1. s,p.d.f
max number of electrons within a subshell
4l+2
magnetic quantum number
ml. particular orbital
-l to +l, including 0.
s subshell, l=0, limits ml to 0, so there is only 1 orbital in the s subshell
p subshell magnetic quantum number
l=1, ml is -1, 0, 1 so 3 orbitals