2.2.1 Shells and orbitals Flashcards
what is a shell?
a group of atomic orbitals with the same principal quantum number, n.
what does n represent?
the principal quantum number (number representing the relative overall energy of each orbital)
what does the principle quantum number indicate?
it indicates the shell that electrons occupy
what does an increased value of n represent?
the larger the value of n, the further away the shell is from the nucleus (tf the higher the energy level)
what is each shell made up of?
a number of atomic orbitals
what is an atomic orbital?
a region around the nucleus that can hold up to 2 electrons, with opposite spin
what are the four types of orbital?
SPDF
what shape is an S orbital?
spherical
from which shell upwards, contains S orbitals?
n=1 (first shell)
how many S orbitals does each shell contain?
1
how many S electrons does each shell contain?
2
what shape does an P orbital have?
3D dumbbell shape
from which shell upwards, contains P orbitals?
n=2
how many P orbitals does each shell contain?
3
how many P electrons could each shell contain?
6
describe what planes each P orbital lies on?
px lying side to side
py top to bottom
p*z front to back
from which shell upwards, contains D orbitals?
n=3
how many D orbitals does each shell contain?
5 D orbitals
how many D electrons could a shell contain?
10 D electrons
from which shell upwards, contains F orbitals?
n=4
how many F orbitals does a shell have?
7
how many F electrons could a shell have?
14
why do electrons not repel each other?
because an electron has a property of opposite spin
describe ‘electrons in boxes’
represents orbitals as a box (with max 2 electrons)
explain how electrons behave
like a particle and a wave
what is electron configuration?
the arrangement of electrons in an atom
which elements also have an F shell?
elements with more than 57 electrons (not in A Level course)
what order does the energy of the electrons in sub shells increase?
s < p < d
how many electrons can an atomic orbital hold?
2
where do atomic orbitals exist?
at specific energy levels (electrons can only be found in these specific levels, not in-between them)
how does the size of s orbitals increase?
the size of the s orbitals increases with increasing shell number
how does the size of p orbitals increase?
the lobes of the p orbitals become larger and longer with increasing shell number
what is spin pair repulsion?
when electrons with the same spin (clockwise or anti-clockwise) repel each other
what is Hund’s rule?
electrons will occupy separate orbitals in the same subshell first to minimise this repulsion and have their spin in the same direction
They will then pair up, with a second electron being added to the first orbital, with its spin in the opposite direction
what is the Pauli Exclusion Principle?
an orbital can only hold two electrons and they must have opposite spin
why can two negatively charge electrons occupy the same orbital, even through there is repulsion?
the energy required to jump to a higher empty orbital is greater than the inter-electron repulsion
what is ground state?
the most stable electronic configuration possible for an atom which has the lowest amount of energy
