what do electron shells contain?
sub shells and orbitals
where are electrons found in modern model of atom?
in specific energy levels called shells surrounding the nucleus
what do shells further from nucleus hold?
hold electrons with higher energy compared to those closer
what is each shell defined by?
a principal quantum number (n =1, 2, 3..) indicating its distance from the nucleus
what are these shells divided in?
sub-shells, which have distinct energy levels and are labelled, s,p,d, and f
where are electrons located within the subshells?
orbitals - regions with a high probability of finding an electron
orbital = a region around the nucleus that can accommodate upto two electrons with opposite spins
what is the capacity to hold lectrons dor subshell s ?
has 1 orbitals and can hold maximum 2 electrons
what is the capacity for sub shell p?
has 3 orbitals and the capacity to hold 6 electrons
what is the capacity for sub shell d?
has 5 orbitals and can hold upto 10 electrons
what is the capacity for sub-shell f?
has 7 orbitals and can hold upto 14 electrons
what is the distribution of sub-shells across the first 4 shells ?
- 1s = total electrons = 2
- 2s, 2p = total electrons = 8
- 3s, 3p,3d = total electrons = 18
- 4s, 4p,4d, 4f = total electrons 32
how much energy do orbitals within the same sub shell have?
equal energy
what can each orbital hold?
can hold 2 electrons, which must have opposite spins ( called spin-pairing)
what shape is s -orbitals?
spherical
what shape are p orbitals?
dumbbell shaped
the 3 p orbitals are oriented at right angles to each other
what directions is the z, y and x
s is a sphere on graph
pz is vertical dumbbell
px is horizontal dumbbell
py is diagonal dumbbell
practise electron configurations
what is the electrons-in-boxes notation?
orbitals are depicted as boxes, with electrons shown as arrows
oppositely directed arrows represent electrons with opposite spins
electron pairing within orbitals only occur with opposite spins
