(1) Atomic Structure Flashcards
What is the mass and charge of Protons, Neutrons and Electrons?
Proton:
- mass = 1
- charge = +1
Neutron:
- mass = 1
- charge = 0
Electron:
- mass = 1/1840
- charge = -1
Define atomic number.
The atomic number is equal to the number of protons.
Define mass number.
The mass number is equal to the number of protons and neutrons combined.
Define relative atomic mass.
Average mass of 1 atom (of an element)
[divided by]
1/12 mass of one atom of 12C
What are isotopes?
Atoms with the same number of protons but a different number of neutrons.
Do isotopes of the same element have the same chemical properties and why?
Yes
Because they have the same electron configuration
Define First Ionisation Energy.
Energy when one mole of electrons is removed from one mole of gaseous atoms to form one mole of gaseous 1+ ions
Write an equation for the 1st Ionisation Energy for Potassium.
K(g) —> K+(g) + e-
Why is the 2nd Ionisation Energy of S higher than the 1st?
The second electron is removed from an ion that already has a positive charge.
What is the model answer for:
The following data shows the first seven successive ionisation energies of a period 3 element. State which element it is and explain your reasoning.
When approaching a question like this, look for where there are large gaps between the ionisation energies:
Model Answer:
- The biggest jump is between the 4th and 5th ionisation energies
- The 5th electron is on the shell closer to the nucleus
- The element must have 4 electrons on its outer shell
- In period 3 this must be silicon
What is the shape of:
- s orbital
- p orbital
- spherical
2. dumbbell
How many s orbitals are in the s subshell?
How many p orbitals are in the p subshell
How many d orbitals are in the d subshell?
1
3
5
Which orbitals have the lowest energy?
The ones closest to the nucleus.
Rule: The higher the orbital, the higher in energy it is.
Which electron on an atom is highest in energy?
The outer most electron - because it is the furthest away from the nucleus.
What does an energy level diagram look like?
- each box represents an orbital - each hold 2 electrons
- each electron is represented by a half arrow, one pointing up, other pointing down
- the half arrows represent the electrons spinning in different directions
3 rules for how to allocate electrons to orbitals?
- Orbitals of lower energy are always filled first
- Atomic orbitals of the same energy fill singly before electrons pair up
- No orbital can have more than 2 electrons
Why is Sulfur a p-block element?
It’s highest energy electron is in the p subshell.
How do you work out the electronic configuration of an ion?
You remove the electrons from the highest energy orbitals in its normal electronic configuration
Which orbital is lower in energy, 4s or 3d?
What must you remember with these 2 orbitals when writing electronic configuration?
4s
- FIRST IN FIRST OUT
- electrons fill 4s first, then 3d
- electrons are removed from 4s first, then 3d
Rule for writing d-block element configurations?
They are more stable when they have a full, or exactly half full sub shell.
Electronic configuration for Chromium?
1s2 2s2 2p6 3s2 3p6 4s1 3d5
Electronic configuration for Copper?
1s2 2s2 2p6 3s2 3p6 4s1 3d10
Electronic configuration Cu2+?
1s2 2s2 2p6 3s2 3p6 3d9
What is the general trend in Ionisation Energy across a period?
- general increase across the period
- this is because across period 3 there is a greater nuclear charge
- same amount of shielding
- so greater attraction between the nucleus and outer electron
