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Topic 1: Atomic Structure & Periodic Table, +, +, +, - - Coggle Diagram
Topic 1: Atomic Structure & Periodic Table
Atom
Structure
Electrons are inside orbitals which form shells. Shells are about the nucleus
Electron charge: -1
Electron mass (amu) : 1/1836
Protons and Neutrons lay inside the nucleus, the centre of an atom
Protons charge: +1
Neutron charge: 0
Proton mass (amu) : 1
Neutron mass (amu) : 1
amu = atomic mass unit
Electrons
Electrons are found in pairs called orbitals
Types of orbitals: s, p, d, f
s - holds 2 electrons
p - holds 6 electrons
p sub-shell has 3 orbitals x y z
d - holds 10 electrons
Electrons fill subshells(s, p, d, f) singly before pairing up
Electrons that fill the same orbital have an opposite spin direction
Orbital notation (oxygen as example)
1s notation:
box notation:
condensed notation(calcium):
f - holds 14 electrons
Electron Configuration determines chemical properties of an element
Trends
Periodicity
The trends across a period
Atomic radius: DECREASES. Due to shielding being constant, more protons in the nucleus and therefore a stronger nuclear pull
1st Ionisation energy: INCREASES. Due to increased proton number, atomic radius decrease and stronger nuclear pull
Electronegativity: INCREASES. Due to more protons, atomic radius decrease and stronger nuclear pull to electron pair
No pattern for MP or BP
Ionisation energy:
Group: DECREASES down the groups. Due to more shielding.
Electrons from the 4s subshell exit before 3d as when they are both filled 4s is on a slightly higher energy
Definitions
ORBITAL: an orbital is an area of space about the nucleus that can hold a maximum of two electrons with opposite spins
Atomic number: The amount of protons in a given atom
Atomic mass number: The total mass of neutrons and protons in a given atom.
Isotope: An atom of the same element that has a different amount of neutrons but the same amount of electrons and protons
Relative isotopic mass: the mass of an isotope of an element relative to one twelfth of the mass of an atom of carbon-12
Relative atomic mass: the weighted mean mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12
Relative molecular mass: The ratio of the average mass of one molecule of an element or compound to one twelfth of the mass of an atom of carbon-12
Relative formula mass: The relative atomic mass of an element is the average mass of its atoms, compared to 1/12th the mass of a carbon-12 atom.
Electronegativity: The ability to attract a pair of electrons
1st Ionisation energy: The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of ions
Mole: The number of nucleons (protons & neutrons) per 1 gram
Successive Ionisation energy: the energy that is required to remove the electron one after the other from each atom in one mole of gaseous atoms to form one mole of ions
Mass Spectrometry
How it works
Ionisation
Electron spray: sample is dissolved in a volatile liquid, squeezed through the tip of a needle that is attatched to the positive terminal of a high voltage supply
X(g) + H(g) = XH(g)
Electron Impact: sample is bombarded with high energy electrons
X(g) = X(g) + e
Acceleration
Positive ions are attracted towards a negatively charged electromagnet (lighter ions are accelerated faster)
Ion drift
Ions pass through a hole in the plate and form a beam to pass down the flight tube
Detection
Ions with the same mass arrive at the same time
Lighter ions arrive first
Positive ions gain electrons and cause a current to flow
Time of flight is recorded
Interpretation of data
Graph
Significant peaks signal main isotopes
Relative abundance out of 100 on the Y-axis,
m/z the ratio of the mass of each ion to its charge on the X-axis (relative mass)
Formula:
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