1.2 - Basic ideas about atoms - Ionisation energy Flashcards
What are the four different sub shell letters and how many orbitals do they have? What is the maximum number of electrons each orbital can hold?
- s has 1 orbital and holds max 2 electrons
- p has 3 orbitals and holds max 6 electrons
- d has 5 orbitals and holds max 10 electrons
- f has 7 orbitals and holds max 14 electrons
define ‘orbitals’
is a volume of space around the nucleus where an electron is likely to be found
what is spin pairing?
when an orbital contains two paired up electrons they spin in opposite directions
what is the shape of s orbitals?
a spherical shape
what is the shape of p orbitals?
a dumb-bell shape
why does 4s come before 3d?
it has a lower energy than 3d so it’s filled before 3d is.
what are the exceptions to the 4s before 3d rule?
Copper (Cu) and Chromium (Cr) as they donate one electron from 4s to the 3d
What region on the periodic table is the s sub shell?
Group 1 and 2
What region on the periodic table is the p sub shell?
Group 3-8
What region on the periodic table is the d sub shell?
transition metals
How do you write the electronic configuration of ions?
remove or add electrons from the highest energy occupies sub-shell
e.g
Mg -> Mg2+
1s²2s²2p^63s² -> 1s²2s²2p^6
Define ionisation energy
The energy require to remove one mole of electrons from one mole of gaseous atoms to form one mole of ions with a single positive charge
Write the equation K(g) -> K+(g) + e- for the second ionisation energy?
K+(g) -> K2+(g) + e-
Describe the main features of the graph and explain them
electrons are being removed closer to the nucleus, removing an electron from an increasingly positive ion
Big jumps= change in shell closer to the nucleus
What is the effect of actual nuclear charge?
more protons=greater attraction so harder to remove electrons
What is the effect of shielding effect on inner electrons?
inner electrons shield the outer electrons from the pull of the nucleus os IE lower and ENC decreases
?What is the effect of the size of the atom?
The larger the atomic size, the smaller will be the ionization energy
in a large atom the electrons are further from the pull of the nucelus so easier to remove
What is the effect of the type of electron being removed (spdf)?
the same quantum shell there is a difference in energy between the spdf electrons
what do the peaks on a successive ionisation graph mean?
noble gases, they don’t want to lose any electrons
what do the troughs in a successive ionisation graph mean?
group 1
what does the successive ionisation graph go up in?
periods
what happens to first ionisation energies generally across periods?
they increase because the actual nuclear charge is increasing so there is a greater attraction for the electrons
what happens to first ionisation energies generally down groups?
decrease in first ionisation energies down groups due to increased atomic radius so outer electrons is further from the nucleus
- less attraction and greater shielding by inner electrons so effective nucleus charge decreases
what happens between Be to B?
1s2 2s2 -> 1s2 2s2 2p1
it’s easier to remove as in a sub shell further from the nucleus’s and therefore more shielding so the effective nuclear charge decreases and ionisation energy decreases
what happens between N to O
1s2 2s2 2p3 -> 1s2 2s2 2p4
- now paired up so repulsion makes it easier to remove therefore ionisation energy decreases
what happens from He to Li?
1s2 -> 1s2 2s1
- a new shell further from the nucleus so shielding increases, effective nuclear charge decreases and ionisation energy decreases
By referring to ionisation energies, explain why stable compounds containing K2+ ions are unlikely to form.
The ionisation energy needed to remove one electron from the 3p subshell is very high.
This is due to having a full and stable 3p subshell.
what might the reasons for a sharp change in an successive ionisation energy graph be.
- sharp rises due to the electrons being removed from the inner shell closest to the nucleus
- sharp rises due to electron removed from a shell closes to the nucleus with less shielding
if asked to describe the way in which electrons are arranged in atoms, how would you go about it?
- talk about how the electrons occupy atomic orbitals within the shells (eg first shell has s orbital, second has s and p)
- how many electrons occupy the orbitals
- spin pairing
- orbitals of the same type are grouped together (eg 3p orbitals in an elements subshell)
When comparing the first three ionisation energies of two different atoms, eg Ca+ and K+, what would you talk about?
- value of the first and third IE energy
- value of the second IE energy
