electron structure Flashcards
define an atomic orbital
a region within an atom arround the nucleus that can hold up to 2 electrons with opposite spins
define a shell
a group of atomic orbitals with the same principle quantum number n
shell closest to nucleus has lowest energy and quantum number of 1
whats the max number of electrons the 1st shell can hold? and orbitals?
2 electrons
1 orbital
whats the max number of electrons can the 2nd shell hold? and orbitals?
8 electrons
4 orbitals
whats the max number of electrons the 3rd shell can hold? and orbitals?
18 electrons
9 orbitals
whats the max number of electrons the 4th shell can hold? and orbitals?
32 electrons
16 orbitals
what is a subshell?
a group of the same type of atomic orbitals within a shell
what does an s orbital look like?
spherical shape
what does a p-orbital look like?
a dumb-bell shape
what does a p-subshell look like?
-from n=2 upwards, each shell contains 3 p-orbitals at 90 degrees to one another along the x-,y- and z- axes
-this gives a total of 6p electrons in the p-sub-shell
-each p orbital has a 3D dumb-bell shape with its centre at the nucleus
what does a d orbital look like?
-from n=3 upwards, each shell contains 5 d-orbitals
-this gives a total of 10d electrons in a d sub-shell
what is the aufbau principle?
electrons fill orbitals of lowest energy first
why does 4s orbital fill before 3d?
because the 4s sub-shell has a lower energy than the 3d sub-shell
what is the order of filling orbitals?
1s^2,2s^2,2p^6,3s^3,3p^6,4s^2,3d^10,4p^6
what is the electron configuration of Mg?
1s^2,2s^2,2p^6,3s^2
describe the relative energies of the 2s orbital and each of the three 2p orbitals in a nitrogen atom
-P-orbitals have greater energy than s-orbitals
-three p-orbitals have equal energy
properties of electrons
-negatively charged
-have spin = electrons in an orbital have opposite spins
what are the diffences in electrons with positive and negative ions?
-when positive ions are formed, electrons are removed from the highest energy orbitals
-when negative ions are formed, electrons are gained to the highest energy orbitals
what makes Cr and Cu more stable?
they have full and half-full 4s and 3d sub-shells
how can a d-sub-shell be incomplete?
if its full
if its empty
define a transition element
a d-block element that forms an ion with an incomplete d sub-shell
what happens when transition elements form cations?
they lose their 4s electrons first
why arent Zn and Sc transition metals?
Sc3+= …..3p^6. this ion has an empty d sub-shell therefore not incomplete
Zn2+=……..3d^10. this ion is completely full therefore not incomplete
