1.1 Atomic Structure (part 2) Flashcards
What are the 4 sub shells
S, p, d, f
How many electrons can the s she’ll hold
2
How many electrons can the p she’ll hold
8
How many electrons can the d she’ll hold
18
How many electrons can the f she’ll hold
32
What does each sub-she’ll consist of
Orbitals
What is an orbital
A region which can hold a maximum of two electrons with opposite spins
How many orbitals in the s sub shell
1 (holds a max of 2 electrons)
How many orbitals does a p shell have
3 (holds a max of 6 electrons)
How many orbitals in a d subshell
5 (holds a max of 10 electrons)
How many orbitals in an f subshell
7 (holds a max of 14 electrons)
What symbol is an unpaired electron represented by
An up arrow
What symbol are paired electrons represented by
An up arrow to the left of a down arrow
Why do sub shells have different energies
Shielding from the nucleus
In what order do the energy levels fill with electrons
1s 2s 2p 3s 3p 4s 3d 4p
How does each sub shell fill up
So that electrons remain unpaired if possible
What happens when the subshell is half full
The electrons pair up
Why does the 1s subshell have the lowest energy
It’s closest to the nucleons
What is the electron configuration of nitrogen
1s2 2s2 2p3
What is the electron configuration of potassium
1s2 2s2 2p6 3s2 3p6 4s1
When are chromium and copper more stable
With half full + full 3D shells (3D fills before 4s)
How can electron arrangements be abbreviated
By using the symbol of the previous noble gas
Which electrons are removed first in transition metals
4s
First ionisation energy
Energy needed to remove one electron from each atom in one mole of gaseous atoms
3 factors which influence ionisation energies
- Atomic radius- distance from nucleus to outer electron
- Nuclear charge (no of protons)
- Shells- more shells leads to more shielding
What is the patterns between ionisation energy and ease of removing outer electron
The smaller the ionisation energy, the easier it is to remove outer electron
What is the trend in 1st ionisation energy down a group
It decreases down a group
Why does 1st ionisation energy decrease down a group
- shells increase so shielding increases
- atomic radius increases to outweigh increase in nuclear charge
- nuclear attraction on outer electron decreases so 1st ionisation energy decreases
What is the trend in 1st ionisation energy across a period
Increase in 1st ionisation energy across a period
Why is there an increase in 1st ionisation energy across a period
- shells + shielding remain same
- nuclear charge increases
- atomic radius decreases
- nuclear attraction on outer electron increases so first ionisation energy increases
Why is there a small dip in 1st ionisation energy between group 2 and 3 elements
E.g. Be>B
- borons outer electron in 2p sub shell- further away from nucleus
- easier to remove
Why is there a small dip in 1st ionisation energy between nitrogen and oxygen
(Applies to all group 5>6 elements)
*easier to remove as electrons are now paired- inter-orbital repulsion
Why is there a big drop in 1st ionisation energy between the end of one period and start of the next
- more shells - more shielding
- nuclear attraction decreases
- ionisation energy lower
What happens tomipnisation energy once one electron has been removed
Electrons become harder to remove
First 4 ionisation energy equations of magnesium
1: mg(g) > mg+(g) + e-
2: mg+(g)> mg2+(g) + e-
3: mg2+(g) > mg3+(g) + e-
4: mg3+(g) > mg4+(g) + e-
Altogether: mg4+(g) + 4e-
Why does successive ionisation energy increase
As electrons are removed, fewer electrons are being attracted by the same number of protons. Therefore, attraction sequentially increases as successive ionisation energies increase
What does the pattern of ionisation energy values tell us
The number of electrons in each energy level, and provides evidence for the existence of energy levels
What does it mean if the ionisation energies are increasing in roughly equal steps?
The electrons are being removed from the same shell
What does it mean if there is a big difference in two successive ionisation energies?
The electrons are being removed from different shells
Why is the first ionisation energy of magnesium higher than that of sodium
Magnesium has more protons
Attraction between nucleus and outer electron is higher
Why is the first ionisation energy of neon higher than that of sodium
Neons outer electron is closer to the nucleus than sodiums
Less shielding and stronger attraction between nucleus and outer electron
Why is borons first ionisation energy lower than expected
Electron is being removed from 2p sub shell which is further from nucleus than 2s
