Topic 1 Flashcards
What is an isotope
Are atoms of the same element with different number of neutrons but same number of electrons
Atomic Number
The Number of protons in an atoms Nucleus
Mass Number
Total Number of protons + neutrons
Relative Atomic Mass
Mean weighted mass of an atom of an element compared to 1/12 mass of one carbon-12 atom
Relative Isotopic Mass
Mean weighted mass of an atom of one isotope compared to 1/12 mass of one atom of carbon-12
Relative Formula Mass
Mean weighted mass of a molecule of a compound compared to 1/12 mass of one atom of carbon-12
RAM equation
(mass x abundance)+(mass x abundance) / Total abundance
Abundance equation
(? x Ar1) + [ (100-?) x Ar2 ] / 100
Mass spectrometry
A device that’s used to measure the mass of positive ions and calculating molar mass
First step to mass spectrometry
Ionisation : Sample enters the mass spectrometer in a gaseous form and are bombarded by a beam of high energy electrons which knock off electrons of the atom causing it to become a positive ion
Second step to mass spectrometry
Acceleration: The positive ions then pass through electric plates which cause the ion to accelerate
Third step of mass spectrometry
Deflection: A strong magnetic field causes the ions to defelct their path , ions with a higher mass are deflected less
Fourth step to mass spectrometry
Detection: The on then gets detected by detector. The more ions hit a certain part of the detector it suggests that theres more of that type of isotope
What are Quantam shells
Well defined levels where electrons can exist
what are sub-shells
The path taken by electrons as they move around shell
What are the 4 types of sub-shells and their maximum electron occupancy
S=2
P=6
D=10
F=12
First ionisation energy
Energy change required to remove 1 mole of gaseous electrons from 1 mole of gaseous atoms to form 1 mole of gaseous +1 ions
Second ionisation energy
Energy change required to remove 1 mole of electrons from 1 mole of gaseous +1 ions to from gaseous +2 ions
How does Nucleur Charge effect IE
If there is higher proton muber there is a h=higher force of attraction between positively charged nucleus and negative charged last electron therefore higher amount of energy is required to remove the electron from the atom
How does Atomic radii effect IE
If there’s higher radii between positive nucleus and negative last electron there is less force of attraction therefore less energy is required to remove the electron
How does Electronic Repulsion Effect IE
When 2 electrons are in the same orbital they repel each other which means less energy is required to remove the electron
How does Electron Shielding effect IE
If there is shielding between sub-shells there is repulsion between the sub-shells leading to less energy being required to remove the electron
What is the trend of IE along period
The IE increases due to higher nucleur charge while the atomic raduis and shielding stays the same.
There is higher repulsion but nucleur charge has stronger effect on IE
What is the trend of IE down a group
The IE decreases as there is higher atomic radii due to new sub-shell being added
What is periodicity
Is the regular repeating pattern of physical and chemical properties with increasing atomic number along the period
What happens to atomic raduis as go along the period
The raduis decreases
Why is this
There is a higher nucleur charge which means there is stronger force of attraction between positive nucleus and negative electrons. This force of attraction brings the nucleus and shells closer thus reducing distance
Exceptions in trends of IE along period in period 2
- Boron:The IE decreases as we are removing an electron from a p-subshell which has higher atomic radii and shielding
- Oxygen: The IE decreases as in the p-subshell we are removing the electron from an orbital where 2 electrons are held together which causes repulsion
Exceptions for IE for a long period 3
- Alluminuim: we are removing electrons from p-subshell which has higher shielding and radii
- Sulphur: In the p-subshell there are 2 electrons in the same orbital which causes repulsion
