CH106 Inorganic Chemistry Flashcards
What are the four fundamental forces?
Strong nuclear force
Weak nuclear force
Electromagnetic force
Gravity
What does the strong nuclear force do?
Binds protons and neutrons to make atomic nuclei.
Acts very strongly but over very short distances
What does the weak nuclear force do?
Hold subatomic particles together inside the nucleus.
Very weak and only acts over very short distances.
What does the electromagnetic force do?
It is responsible for the attraction between positive and negative charges.
Weaker than the strong force but acts over an infinite distance
What does the force of gravity do?
Attracts matter to other matter.
Verty weak but acts over an infinite distance
What are the five ways elements can be formed?
The big bang
Stellar nucleosynthesis
Supernova nucleosynthesis
Radioactive decay of heavy elements
Human interference
What is stellar nucleosynthesis?
Fusion of light elements (up to iron)
What is supernova nucleosynthesis?
The fusion of heavier elements (eg O) after an old star has exploded. This creates elements Ni up to U
What is effective nuclear charge?
The positive nuclear charge that an electron experiences from the nucleus.
It is the nuclear charge - a factor due to electron shielding
What is the trend of effective nuclear charge across a period?
What is the trend of effective nuclear charge down a group?
The nuclear charge increase across the group due to the increasing nuclear charge
The effective nuclear charge decreased down the group due to increased electron shielding
What is atomic radius?
This is defined as half the distance between two atomic nuclei in an element
What is the trend of atomic radius across a period?
What is the trend of atomic radius down the group?
The atomic radius decreases across the period as the effective nuclear charge increases pulling the electrons close to the nucleus
The atomic radius increases down the group as new electron shells are being added
What is ionisation energy?
This is the energy required to remove the outermost electron from a neutral atom in a gaseus state
What is the trend of ionisation energy across the period?
What is the trend of ionisation energy down the group?
The ionisation energy increases across the period due to the increasing effective nuclear charge thus the electrons are close to the nucleus.
The ionisation energy decreases down the group due to the decreasing effective nuclear charge this the electrons are further from the nucleus.
What cause the abnormalities in ionisation energy across the period?
This is due to how the atomic orbitals are filled. Fully filled or half filled shells are more stable than random electron arangments.
What is electron affinity?
This is the change in energy due to the addition of an electron to a neutral atom in a gaseous state.
What is electronegativity?
This is the relative measure of the ability of an atom in a molecule to attract bonding electrons to itself.
What is the trend in electronegativity across the period?
What is the trend in electronegativity down the group?
The electronegativity increases across the period due to the increasing effective nuclear charge.
The electronegativity deacreases down the group as new shells of electrons are added thus the atomic radii increases.
Important factor regarding oxidation states.
Empty shells, half filled shells and fully filled shells are all favourable.
Considering oxidation states, what will make an a compound unstable?
An element with an abnormal oxidation state.
An oxidation state that breaks the group oxidation states (the oxidation state is greater than the number of valence electrons)
What are the two main ideas of VSEPR theory?
Electrons will position to minimise repulsions.
The molecular shape will be dependant on the valence electrons, both bonding and lone pairs.
What shape is created when a molecule has two pairs of electrons?
What are the bond angles?
Linear
180 degrees
What shape is created when a molecule has three pairs of electrons?
What are the bond angles?
Trigonal planar
120 degrees
What shape is created when a molecule has four pairs of electrons?
What are the bond angles?
Tetrahedral
109.5 degrees
What shape is created when a molecule has 5 pairs of electrons?
What are the bond angles?
Trigonal bipyramidal
90, 120 and 180 degrees
What shape is created when a molecule has 6 pairs of electrons?
What are the bond angles?
octahedral
90 and 180 degrees
What is this core shape?
Linear
What is this core shape?
Trigonal planar
What is this core shape?
Tetrahedral
What is this core shape?
Trigonal bipyrmaidal
What is this core shape?
Octahedral
What is this derived shape?
Bent/angular
What is this derived shape?
Trigonal pyramidal
What is this derived shape?
T-shaped
What is this derived shape?
Square planar
What is this derived shape?
Disphenoidal (see-saw)
What is this derived shape?
Square pyramidal
What does amphoteric mean?
This means a substance can act as both an acid and a base
What is Bronsted’s definition of an acid?
A species that donates a proton (H+)
What is Bronsted’s definition of a base?
A species that accepts a proton (H+)
What is a Lewis acid?
Accepts electrons
What is a Lewis base?
Donates electrons
What increases the strength of hydrogen bonding?
A large difference in charge
