Unit Three Flashcards
Equation to find either frequency or wavelength of light
c = f λ c = 3.00 x 10^8 (m/s) f = frequency (Hz) λ = wavelength (m)
How are frequency and wavelength related?
They are inversely related, so as one goes up, the other goes down and vice versa. This is because c is constant.
Equation that relates the amount of energy released or absorbed and the frequency of the light
E = hf E = energy (J) h = constant, 6.63 x 10^-34 (J-s) f = frequency (Hz)
Excited
When an electron absorbs energy and moves to a higher energy level
Ground state/ground level
When an electron loses energy and goes back to its ground level (which is not always the first energy level)
Frequency and color of light depend on
How much energy is released
Energy levels farther away from the nucleus have
More energy than the ones closer
How do electrons move between the levels?
If the right color (and therefore frequency) of light is absorbed, the electron gets enough light to move to a higher energy level.
To go from the second to first level does an electron need to absorb or give off energy?
From the first to second?
Give off
Absorb
Do atoms of different elements have different numbers of electrons?
Yes but not ions
Do different atoms let off the same color light?
No because they have different amounts of electrons, you don’t know which energy level they’re starting at, and the atomic spectrum.
Why don’t electrons collapse into the nucleus?
The velocity of the electrons allows them to not be pulled into the nucleus because it counteracts the pull of the nucleus.
Energy levels
The number of rings of electrons an atom has or ion has; this corresponds to the periods of the periodic table. There are a total of 7 energy levels.
Sublevels (shapes)
Located inside energy levels. Each sublevel is given a name (s, p, d, f, etc.)
Orbitals
Located inside sublevel said. Different sub levels have different numbers of orbitals.
How many electrons can fit in each orbital?
2 and ONLY 2
What sub levels exist in the 1st energy level?
s
What sub levels exist in the 2nd energy level?
s and p
What sublevels exist in the 3rd energy level?
s, p, and d
What sublevels exist in the 4th energy level?
s, p, d, and f
How many orbitals does the s sublevel have?
1 (so 2 electrons in total)
How many orbitals does the p sublevel have?
3 (so a total of 6 electrons)
How many orbitals does the d sublevel have?
5 (so a total of 10 electrons)
How many orbitals does the f sublevel have?
7 (so a total of 14 electrons)
How many electrons can the 1st energy level have in total?
2
How many electrons can the 2nd energy level fit in total?
8
How many electrons can the 3rd energy level fit in total?
18
How many electrons can the 4th energy level fit in total?
32
Aufbau principle
Electrons will fill up the lowest energy level first
Pauli Exclusion Principle
No two electrons can occupy the same energy level and orbital unless they are spinning in opposite directions. This is because their negative charges repel.
Hund’s Rule
Electrons will spread out over the orbitals in the same shape, before pairing themselves up.
Noble Gas Configuration
- Choose the Noble Gas that comes before that element (so even if the element is a noble gas, still choose the noble gas before it and work from there).
- Put the noble gas’s symbol in brackets.
- Then write the remainder of the electron configuration.
An up arrow means that the electron is spinning…
clockwise
A down arrow means that the electron is spinning…
counterclockwise
Longhand electron configuration for sodium
1s^22s^22p^63s^1
Noble gas configuration for sodium
[Ne] 3s^1
Orbital notation for sodium
Do it on paper but you should be able to do this
Shielding
When electrons in the energy levels besides the outer valence shell weaken the force of the protons on the electrons in the outer shell. Basically, they “shield” the outer electrons from some of the attractive force of the nucleus.
How do you know how much the valence electrons are being shielded?
Calculate the charge of the protons in the atom (the atomic number). Then, count how many electrons are in the non-valence energy shells. Subtract this number from the number of protons, and that is the force of attraction on the valence electrons.
What determines the size of the atom?
The attraction between the nucleus and outer energy level. If this is the same, then the amount of energy levels.
How does the atomic radius compare, going from left to right across a period on the periodic table?
It gets smaller. This is because there is more attraction as the period goes on, because the electrons aren’t being shielded as much, so they are smaller further down.
How does atomic radius compare, going from the top to the bottom of a family on the periodic table?
It gets bigger. This is because they have the same force of attraction, but because the lower ones have more energy levels, they are naturally bigger.
Ionization energy
The amount of energy that it takes to completely remove an electron from an atom.
Which is higher, the first ionization energy or the second ionization energy?
Second
Why do the noble gases have such a high ionization energy?
They have a full valence shell so they’re very stable and really don’t want to lose electrons so it takes a large amount of energy to lose an electron.
How does the ionization energy compare as you move from left to right across a period of the periodic table?
It increases because the atomic radius is getting smaller which means there is more attraction so it is harder to get an electron away.
How does the ionization energy compare, moving up to down on the periodic table?
It decreases because going down there are more energy levels so naturally they’re at a further distance from the nucleus and attractive force so it takes less energy to remove one.
Math you need to know how to do
Calculate using:
c = fλ
E = hf
DON’T FORGET UNITS
Do orbital notation
Calculate electron shielding, the nucleus charge, and and the attraction felt by energy levels from the nucleus
Calculate ionization energy
Why does magnesium have such a high third ionization energy?
If you take away two electrons it becomes Neon which is a noble gas so it’s very hard to take away a third electron.
