Periodic Table Flashcards
How does the distance away from the nucleus affect the energy of an energy level?
An orbital has more energy when it’s further away from the nucleus
How many electrons can the first shell hold?
2
How many electrons can the 2nd shell hold?
8
How many electrons can the 3rd shell hold?
18
How many electrons can the 4th shell hold?
32
How many electrons can an orbital hold?
2
How many orbitals does the s sub-shell have?
1
How many orbitals does the p sub-shell have?
3
How many orbitals does the d sub-shell have?
5
How many orbitals does the f sub-shell have?
7
What shape is an s orbital?
A spherical shape
What shape is a p orbital?
A dumb-bell shape
Which sub-shell is filled after 3p?
- 4s, 3d is filled after 4s as it is higher in energy than 4s
- Electrons from 4s are removed before electrons from 3d when forming ions
When filling box diagrams do you fill the boxes 2 electrons at a time?
- No, you fill each box with one electron each first and then backfill
- When a sub-shell is full you can move onto the next sub-shell
- One arrow in each box in box diagrams should be pointing up, one should be pointing down
What is the electronic configuration of copper?
[Ar] 4s^1 3d^10
What is the electronic configuration of chromium?
[Ar] 4s^1 3d^5
Why do shells that are further away from the nucleus have more energy?
Electrons need energy to climb shells meaning that electrons furthest away from the nucleus have climbed the most shells so they must have the highest energy. The shells that have the electrons with the highest energy have the highest energy
Why do electrons in the same orbitals have arrows pointing in opposite directions?
It represents the electron’s tendency to repel each other
Why is electrons added to and removed from the 4s orbital before the 3d orbital?
The 3d sub-shell has more energy than the 4s sub-shell so the 4s sub-shell is filled and has electrons removed from it before the 3d sub-shell
What is ionisation energy?
The energy required to remove an outer electron from the attractive force of the nucleus
What is first ionisation energy?
The energy required to remove one electron from each atom in one mole of the gaseous element to form one mole of gaseous 1+ ions
What is the trend in ionisation energy going down a group?
Ionisation energy decreases going down a group as the atomic radius increases, this means that the nuclear attraction experienced by the outer electrons decreases as outer electrons are further away and experience a greater shielding effect as the number of shells increases going down the group
Why does ionisation energy increase going across a period?
The amount of protons in the nucleus increases meaning that the nuclear attraction increases. The shielding effect that the outer electrons experience is similar across a period as they’re in the same shell, the atomic radius also decreases going across a period as there is a stronger nuclear attraction because the number of protons increases as you go across a group. A smaller atomic radius means a higher ionisation energy
Why does the ionisation energy decrease between magnesium and aluminium (and beryllium and boron) when the trend is that ionisation energy increases across a period?
Mg has 12 electrons, aluminium has 13. Aluminium’s valence electron is shielded more as it’s from the 3p orbital and is therefore shielded by the two electrons in the 3s orbital. Magnesium’s valence electron is in the 3s orbital so it’s shielded by less electrons. Aluminium’s valence electron also experiences less nuclear attraction as it is in the 3p orbital which has a slightly higher energy level than the 3s orbital, therefore it’s further away from the nucleus and experiences less nuclear attraction. Experiencing less nuclar attraction and more shielding means that it takes less energy to remove Aluminium’s valence electron and therefore aluminium has a lower first ionisation energy.
Why does the ionisation decrease between nitrogen and oxygen when the ionisation energy is meant to increase across a period?
The ionisation energy decreases between oxygen and nitrogen because nitrogen has no orbitals in the 2p sub-shell that are fully filled, whereas oxygen has one orbital that is fully filled in the 2p sub-shell. The outer electron is now spin paired in the first 2p orbital. The electrons that are spin paired the ionisation energy is lower for oxygen than nitrogen
Why does the melting point increase across period 3 metals?
The atomic radius of the cations decreases while the charge increases, there are also more delocalised electrons so the strength of the metallic bonds is increased meaning that the melting point is higher
What are the structures of the period 3 elements?
- Na, Mg, Al - giant metallic lattice
- Si - giant covalent lattice
- P, S, Cl - simple molecules
- Ar - atoms
How does metallic bonding work?
There are strong electrostatic forces of attraction between cations and delocalised electrons as they’re oppositely charged
What is a giant covalent lattice?
A network of atoms joined together by covalent bonds
What is a simple molecule?
A molecule with strong covalent bonds between atoms but weak intermolecular forces between molecules meaning they have low melting and boiling points
What type of bonding do noble gases have?
Weak interatomic forces between atoms
Explain the trends in boiling point in period 3
- Na, Mg and Al have high boiling points due to the strong electrostatic forces of attraction between cations and delocalised electrons
- Silicon has a high boiling point due to their strong covalent bonds that have to be broken
- P, S and Cl have low boiling points because of the weak intermolecular forces that have to be overcome (the covalent bonds don’t need to be overcome for the molecule to boil or melt
- Ar has a low boiling point due to the weak interatomic forces that have to be overcome
Why are metals good conductors?
They have delocalised electrons that can move throughout the structure making it a good conductor
Is silicon a good conductor?
No, it has a limited number of electrons that can move through the structure meaning it’s a poor conductor
Are simple molecules and noble gases good conductors?
No, they have no free electrons meaning they’re poor conductors of electricity