chp 2 general chem DAT Flashcards
atomic symbols -
left bottom number
protons
left top number
atomic mass
atomic mass =
protons + neutrons
neutrons =
atomic mass - protons
electrons =
protons = electrons
unless element has a charge then sub or add the charge
bohr model of the atom
1913 Niels Bohr created the first working model of hydrogen atom
- as energy moves up the next shell , the shell gets smaller and further from the nucleus
what is quantization ?
the concept that a physical quantity, like energy, can only exist in discrete, specific values
what are electrons ?
they zoom through 3D atomic or molecular orbitals
4 types of orbital
S,P,D,F
s orbital
shaped like spheres. not 2D circle. low energy orbitals are buried inside the higher energy orbitals
p orbitals
shaped like dumbbells. each energy level has 3 p orbitals (horizontal, vertical and diagonal )
when we say 2p shell we refer to 3 separate p orbitals
d orbitals
looks like a 4 leaf clover. there are 5 diff d orbitals per shell.
transition metals
are bright colored because they have a funky d orbital shaped that allows electrons in the d orbitals to absorb colored light and promote higher energy orbitals within d shell
f orbitals
they have 7 diff shapes.
s block
2 columns wide. 1 s orbital per shell
f block
14 column wide, 7 f orbitals per shell
d block
10 columns wide. 5 d orbitals per shell
f block
6 columns wide . 3 f orbitals per shell
principle - quantum number
1,2,3,4=n
this tells us in which shell the electron is in or how far its from the nucleus
azimuthal - quantum number
L = 0,1,2,3
tell us in which orbital the electron is in
0,1,2,3->s,p,d,f
magnetic -quantum number
m = neg to pos number
tells us in which p orbital , d orbital or f orbital electron Is in
ex if its in p orbital, they only have 3 diff orbitals so -1,0,1
ms -quantum number
spin number
equal to -1/2 or 1/2
what does electron conf mean ?
description of quantum numbers and orbitals
1s2
1= is the principal quant number or energy n=1
s = what kind of orbital these electrons are in s means L = 0
2 = shows how many electrons are in the orbital
oxygen ex electron conf
1s22s22p4
2p4 means there are 4 electron using the 3 p orbitals ( 3 p because there are 3 p orbital types )
hunds rule
electrons never pair up unless there is no more space
condense electron conf
you write the noble gas before the element and the rest of the electron conf
bromine condense conf
Ar-4s23d104p5
valance vs core electrons
valence e are the ones in the outermost shell and core e are inside the inner shells.
valence electrons
the ones with the largest Principle quantum number
exception for valence electrons
elements in the d block , d shell electrons are also valence.
atomic orbital energy diagram
the larger the electrons principle quantum number the further away from the nucleus it is and higher in energy
rules for e-
aufbau: electrons fill the lowest energy orbitals firs
hunds ; electron don’t pair up until they have to
pauli ; no 2 electrons in the same atom can have the same quantum number
excited vs ground state
ground state is the normal regular state
excited state is when an electron absorbs a photon of light which get promoted into a higher energy shell
when a electron falls back to ground state it emits color
paramagnetic vs diamagnetic
paramagnetic = unpaired electrons - which makes them attracted to magnets
(ODD number of e)
diamagnetic = all electrons are paired - they slightly resell magnetic fields (ODD or EVEN number of e)
a photons energy
the particle of light (photon)can be calculated using
Ephoton = hf=hc/wavelenght
photons energy
as energy increases , frequency increases = wavelength decreases
photoelectric effet to function …
metal has to be hit with a photon with enough energy. ( photon must have high frequency and low wavelength )
