Orbitals Flashcards
What are electrons arranged in?
Shells
What do shells have?
Sub shells called orbitals
Orbitals can hold 2 electrons
What are orbitals in terms of size?
Smaller than sub shells and much smaller than shells
Why do orbitals have strange letters representing them?
P orbital is an orbital that looks a bit like a chromatid
S orbital looks to be half the size
What do electrons do in orbitals?
Spin in opposite directions
What are orbitals?
A region of space that electrons are most likely to be within .
What is shell 2 made up of?
1s, (2 electrons each)
3p (2 electrons each for the p orbitals ) {px, pz, py}
Orbitals
What are the letters representing the sub levels?
S, p, d, f
How many orbitals are in s sub level
And what is the maximum electrons in said orbital?
1
2 e-
How many orbitals are in p sub level
And what is the maximum electrons in said orbital?
3
6e-
How many orbitals are in d sub level
And what is the maximum electrons in said orbital?
5
10 e-
How many orbitals are in f sub level
And what is the maximum electrons in said orbital?
7
14 e-
What does the number in front of the letter mean?
Shell number/ energy level
What does the box mean
An orbital , when they are together it is a sub shell.
What is a sub shell ?
A thing that has a certain number of orbitals in it
What word do we use in place of shell now?
Energy level
What are the sub shells in the 4th energy level?
4s,4p,4d,4f
All sub shells have a certain number of orbitals in them
How many electrons can an orbital hold?
2
What sub shells are in energy level 3?
3d, 3p,3s
What orbitals are in energy level 2?
2p,2s
What sub shell is in energy level 1?
1s
What is Aufbau s principle?
Electrons enter the lowest energy orbital available
What is hunds rule?
Electrons prefer to occupy orbitals on their own and only pair up when no empty orbitals of the same energy are available
What analogy best fits hunds and aufbaus rule?
A senior person on the bus:
A: sits down on the first floor of a bus because its easier than climbing upstairs
H: sits down on the first floor as they prefer to sit on an empty seat rather than one with somebody already sitting on one
Why do the electrons spin in opposing directions?
Because they are of like charges
What are the rules aside from A and H
Electrons fill up 1s then 2s then 2p 3s, 3p then 4s then 3d
What happens to the orbitals and sub shells when electrons are lost?
The highest energy electrons are lost when an ion is formed
{ 4s electrons are lost before 3d as once 4s and 3d are occupied, 4s has a higher energy than 3d and moves above it
What are electrons represented by?
Arrows
What are the exceptions ?
Normal: 1s2,2s2,2p6,3s2,3p6,4s2,3d4
Cu and Cr don’t have the typical electron structure.
Cr: has : 1s2, 2s2, 2p6 , 3s2, 3p6, 4s1, 3d5
Cu has: 1s2,2s2,2p6,3s2,3p6,4s1,3d10
Why is cu and cr different
The method is more stable i.e 4s1 and 3d5 is more stable than 4s2, 3d4 as all of them are singly filled as opposed to 4s being full and 3d just having 4 singly filled
What happens when electrons are added or removed from an atom?
Ionisation
What is the first ionisation energy ?
The energy required to remove the first electron (in valence shell)
How do you write ionisation energy equations ?
First ionisation is the energy needed to remove one electron from each atom in one mole of gaseous atoms to form 1 mole of gaseous 1+ ions
- you need to use state symbols (g)
- always refer to 1 mole of atoms
- the lower the ionisation energy, the easier it is to form a positive ion
What are some factors affecting ionisation energy?
- nuclear charge
- distance from nucleus
- shielding
How does nuclear charge affect ionisation energy?
More protons= more electrostatic attraction to electrons
How does distance affect ionisation ?
Big distance= weaker electrostatic attraction to nucleus
How does shielding affect ionisation energy ?
More energy levels= weaker attraction to nucleus
What is second ionisation energy?
The energy required to remove an electron from each 1+ion in one mole of gaseous ions
What is the difference between 1st and 2nd ionisation energy?
Second ionisation energies are greater bc its the removal of an electron from an ion
What is a successive ionisation energy ?
You can remove all the electrons and leave only the nucleus, you do so by removing one at a time, this process is called successive ionisation energy
Trends in ionisation energy?
First decreases down a group: proof of energy levels as each element has one more than pre.
First increases across periods: harder to remove outer e as no. Of protons are increasing
Why may drops occur in trends ?(periods)
Mg, Al
Aluminium’s outer electron is in a 3p orbital instead of a 3s … electron is found further from nucleus
3p has additional shielding
These both override the effect of nuclear charge
P,S
Shielding is the same however with sulfur , an electron is being removed from an orbital containgin 2 e while in phosphorus its only one
How is ionisation energy (successive) evidence for shell structure?
In each shell the ionisation energy increases because electrons are being removed.
Because of ionisation, there’s less repulsion amongst the remaining electrons and the nucleus
Large jumps in ionisation energy is when a new shell is broken into
Graphs can help predict what the electronic structure of the element is
What is an ionic bond?
The electrostatic attraction between oppositely charged ions
What is the compound ion for ammonium
NH4+
What is the formula for carbonate ions ?
CO3 2-
What is the formula for a hydroxide ion
OH-
What is the formula of a nitrate ion?
NO3 -
Formula for surface ion
SO4 2-
What is diamond in comparison to graphite ?
- high melting point 3800K
- super hard
- vibrations travel easily through the stiff lattice so its a good thermal conductor
- can’t conduct electricity, all the outer electrons are held in localized bonds
- like graphite , diamond won’t dissolve in any solvent
What is dative covalent
In a normal single covalent bond, atoms share a pair of electrons -with one electron coming from each atom. In a coordinate bond also known as a dative covalent bond, one of the atoms provides both of the shared electrons
What are some examples of dative covalent bonds?
Ammonium ion (NH4+)
(FROMED WHEN THE TWO REMAINING ELECTRONS ON nh3 COME INTO CONTACT WITH AN H+ION )
Hydroxonium ion (H3O+) When one pair of the 4 electrons remaining binds to an H+ ion )
How has atomic structure evolved over time ?
Thompson -> Rutherford-> Bohr-> quantum
What is the relative charges and masses of protons, neutrons and electrons ?
(In relative to C12)
Protons: +1
1
Neutrons:0
1
Electrons: -1
1/2000What letter represent the mass number and the atomic number ?
Mass number :A
Atomic number:Z
