Topic 2 Flashcards
What are the 3 types of Chemical Bonds?
Ionic Bonding
Covalent Bonds
Metallic Bonding
What is Ionic Bonding Between?
Metals and Non metals
What is the transfer of electrons in ionic compunds?
There is a transfer of electrons to form a Cation and Anion
What is the Physical property of Ionic compounds?
They are rigid and brittle
What are Ionic compounds held together by?
Electrostatic forces
What is the Conductivity of ionic compounds?
They are poor conductors when solid but good conductors when dissolved in water
What are covalent bonds between?
2 non-metals
What are the electrons like in Covalent bonds?
The non-metals share electrons
What is the structure of Covalent bonds?
They have a molecular structure
What States do Molecular structures exist as?
They exist as gasses or liquids with low bond polarity
What is the Bond polarity of covalent bonds?
Low bond polarity
What are the 2 types of Covalent bonds?
Non-polar (Pure Covalent) and Polar
What is the sharing of electrons in Non-polar (pure covalent) bonds?
Equal sharing of electrons
Where is equal sharing of electrons found?
In diatomic and homonuclear molecules
What is the sharing of electrons in Polar molecules?
Unequal sharing of electrons resulting in electronegativity
What does the unequal sharing of electrons cause?
Difference in electronegativity
Where is the capacity for an atom to attract electrons found?
In a bond
What does a high electronegativity mean?
High attractions to electrons
What is the formula to calculate electronegativity?
|(First electronegativity)-(Second electronegativity)|
What does an electronegativity of >2 mean?
Ionic bond
What does an Electronegativity value of < 2 mean?
Polar covalent bond
What does an Electronegativity value of 0 mean?
Covalent
What are Metallic Bonds?
Bonds between 2 metals
How are electrons in extended structures?
A sea of displaced electrons in an extended structures
What are the Physical properties of Metallic bonds?
Malleable and ductile and good conductors of heat and electricity.
Which atoms do not obey the octet rule?
Atoms in period 3 and beyond
What is the formal charge of an atom?
Fc = valence electrons - electrons in lone pairs - 1/2 electrons in covalent bonds
What do lewis structures show?
Arrangements of electrons in a molecule but not the molecular shape
What does VSEPR tell us?
The molecular shape of atoms
Where does Hybridizing occur?
In covalent bonds
What is Hybridizing?
The mixing of orbitals to form a new set of orbitals
What is the energy of Hybrid orbitals?
The hybrid orbitals are degenerate to each other
What do Single bonds have?
Sigma bonds
What do Double bonds have?
One sigma and one pi
What do Triple bonds have?
2 pi and one sigma
What is Bond Strength related to?
It length and energy
How is Bond Strength related to bond length?
The greater the bond length the smaller the bond energy
What is Bond Length?
The distance that separates nuclei in covalent bonds
Which of bond breaking and forming is exothermic and endothermic?
Bond breaking is endothermic and bond forming is exothermic
What is the Formula for Enthalpy of a reaction?
(sum of the bond energy of reactants) - (sum of the bond energy of products)
What are Cations and Anions held together by?
Electrostatic forces
What is the formula for electrostatic forces?
q1q2/d^2
What is Lattice energy?
Lattice energy is the strength of ionic bonds
When is Lattice Energy released?
When gaseous ions combine to form the ionic solid
What is the Atomic Size trend on the period table?
It increases as you move down and to the left
What does Molecular Orbital theory use as a basis for its ideas?
Quantum mechanics
Where are electrons found in Molecular Orbital theory?
They are found in molecular orbitals
What do Molecular Orbitals represent?
The delocalization of electrons over an entire molecule
What are Molecular Orbitals the result of?
The coupling of atomic orbitals
What causes Constructive orbitals?
Constructive orbitals form when the phase of the atomic orbitals are the same
What causes Destructive orbitals?
Destructive orbitals form when the phase of the atomic orbitals are different
Which are higher energy destructive or constructive molecular orbitals?
Destructive molecular orbitals
What do sigma bonds form from?
Bonds between hybrid orbitals
What do pi bonds form from?
Bonds between non-hybrid orbitals
How are Bond order and Strength related?
As bond order increases, bond strength increases
What is Bond order a measure of?
Bond strength
What is electron group configuration based on?
The number of electron groups around the central atom
What is a Dipole Moment?
When a molecule has a slightly positive charge and a slightly negative charge
When does Resonance occur?
When molecules have more than one plausible lewis structure and the true structure is a resonance hybrid of all the contributing lewis structures
What is the formation of molecular orbitals when p atomic orbitals make molecular orbitals?
They create 2πp molecular orbitals and 1σbond with the sigma orbital being higher energy than the pi orbital
What changes about the molecular orbitals that p forms when it comes to O and F?
In O and F the bonding molecular orbitals are flipped so that the 2pi* bonds are higher in energy than the 1σ bond
What happens as bond order increases?
Bond strength increases so bond length decreases
Why are the atomic orbitals of oxygen lower energy than nitrogen?
Because oxygen has a higher effective nuclear charge so it holds its electrons more tightly which is more stable
How is the energy of orbitals and Zeff related?
Orbitals with higher effective nuclear charge hold electrons more tightly so they have a lower energy because they are more stable
What is the Arrhenius definition of an Acid?
Substance that ionized in a solution to produce H+ or H3O+
What is an Arrhenius Base?
A substance that ionizes to produce OH- (hydroxide)
What is a Bronsted Lowry Acid?
A substance that donates H+ to another substance
What is a Bronsted Lowry Base?
Substance that accepts H+
What is a Lewis Acid?
An electron-pair acceptor
What is a Lewis Base?
An electron-pair donor
What does complete ionization mean?
A strong acid or base
What does partial ionization mean?
A weak acid or base
What makes hybridized orbital bonds?
σ bonds
What makes unhybridized orbital bonds?
π bonds
How is the strength of acids and bases measured?
By the equilibrium constant, k
What is the formula for the equilibrium constant?
Products over reactants to the power of their coefficients
What does a high acid ionization or base ionization mean?
A strong acid or base
What does decreasing Ka or Kb mean?
Decreasing strength of acid or base
What will a strong acid produce?
A neutral conjugate base
What will a weak acid produce?
A weak conjugate base
What will a weak base produce?
A weak conjugate acid
What will a strong base produce?
A neutral conjugate
What will any compound with a Ka smaller than water produce??
A strong conjugate base
What are the properties of salt produced in a neutralization reaction?
They may or may not produce acid base properties
How can you predict the properties of salt produced in a neutralization reaction?
By seeing what they come from
What does Polyprotic mean?
An acid has more than one acidic proton
What does Amphoteric or Amphiprotic mean?
Something can act as an acid or base
What are the types of Weak organic Acids?
Carboxylic acids (ROOH) Ammonium ions (R3NH+)
What are the types of weak organic bases?
Carboxylate ions (RCOO-) Amines (R3N)
What are the Strong acids?
Hydrochloric acid (HCl) Hydrobromic acid (HBr) Hydroiodic acid (HI) Nitric acid (HNO3) Sulphuric Acid (H2SO4) Perchloric acid (HClO4)
What affects the strength of binary acids?
Affected by bond length on bond polarity
What is the trend in strength of Binary acids down a group?
As you move down a group the acid strength increases?
Why does Binary Acid strength increase as you move down a group?
Because atom size increases which means bond length increase which means bond strength decreases makes the H+ more easily ionizable
What is the Trend of Binary Acid strength as you move across a period?
Acid strength increases
Why does the Strength of a Binary acid increase as you move across a period?
This is because bond polarity increases meaning that the central atom is more electronegative so it attracts electrons more strongly which means the H+ becomes more easily ionizable
What factors affect the strength of Oxyacids?
The electronegativity of the central atom and the number of oxygens around the central atom
What is the trend of oxyacids related to the number of oxygens?
As the number of oxygens increases the acid strength increases
Why does the acid strength increase as the number of oxygens increase?
Because the oxygens are more electronegative so they attract electrons more strongly which makes H+ easily ionizable
What is the trend of Oxyacids relating to the central atom?
As the electronegativity of the central atom increases the stronger the acid
Why does the strength of an acid increase as the strength of the central atom increases?
This is because electrons are more tightly held to the negative side which makes the H+ more easily ionizable
