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60 Cards in this Set
- Front
- Back
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Define first ionisation energy
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The energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous +1 ions.
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Define second ionisation energy
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The energy required to remove one electron from each ion in one mole of gaseous +1 ions to form one mole of gaseous +2 ions.
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Define successive ionisation energy
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A measure of the energy required to remove one electron in turn from an element
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Which 3 factors effect the strength of ionisation energy and how do they affect it?
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- Nuclear Charge: Increased attraction between protons and outer electrons, increases ionisation energy
- Atomic Radius: Increased radius moves electrons further away from nucleus, decreases ionisation energy - Electron Shielding: More shells creates negative repulsion between shells, reducing affect of nuclear attraction and decreasing ionisation energy |
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How is an atom structured in terms of shells + orbitals?
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1. The Atom
2. N-Shells (N = principal quantum number) 3. Sub-Shells (S, P, D & F) 4. Orbitals (S = 1, P = Px, Py & Pz, D = 5, F = 7) |
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What is a shell?
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a group of atomic orbitals with the same principal quantum number
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What is the atomic orbital?
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A region of space around an atom's nucleus which can be occupied by 2 electrons in opposite spins
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How many electrons can fit in an orbital?
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2 electrons in opposite spins (spin up and spin down)
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What does the principal quantum number represent?
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The relative overall energy of each orbital
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Which orbitals are occupied in each shell?
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1 = S
2 = S, P 3 = S, P, D 4= S, P, D, F |
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Why is 4S occupied before 3D?
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it has a lower energy level
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Where does ionic bonding occur?
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In metals and non metals
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Where does covalent bonding occur?
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In two non metals
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Where does metallic bonding occur?
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in two metals
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What is a lone pair?
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A pair of electrons not involved in bonding
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What is a dative covalent bond?
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A shared pair of electrons with both electrons originating from one atom
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Define metallic bonding
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The electrostatic attraction between a positive metal ion and the sea of delocalised electrons
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Describe properties of metals.
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- High melting and boiling points
- Conducts electricity (free electrons) - Malleable & Ductile |
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Define malleable
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Can be hammered into shape
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Define ductile
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Can be drawn into wires
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What is an alloy?
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A mixture of 2 or more metals
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How are the properties of alloys different when compared to metals?
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they are harder as the large metal ions replace smaller ions to reduce sliding
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Define ionic bonding.
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The electrostatic attraction between oppositely charged ions
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What are the properties of ionic compounds?
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- High melting + boiling points
- Conducts electricity in liquid (ions are free to move) - Nonconductive as solid (no free ions) - Soluble in polar solvents - breaks down lattice |
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Why is water a good solvent for ionic compounds?
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- polar molecules are attractive to oppositely charged ions in lattice
- Attraction breaks down the ionic bond - They are surrounded by water |
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What is the exception for an expected ionic bond being simple molecular instead?
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It is liquid at room temperature and therefore cannot be ionic
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What are some properties of salts?
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- Crystalline: Ions attract to form arrangement
- High M.P: Strong bonds - Soluble in water: water molecules break it down - Conducts electricity when aqueous: has free electrons |
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Define covalent bonding
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The sharing of a pair of electrons which are attracted to the protons in the nucleus of the neighbouring atom it is bonded to
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Name the two types of covalent bonds
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- Giant covalent
- Simple molecular |
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What are the properties of giant covalent structures?
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- High M.P: Strong bonds
- non-conductive due to no free electrons - Insoluble - lattice cannot be broken |
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What are the properties of simple molecular structures?
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- Low M.P. = weak intermolecular forces
- Non Conductive - no free electrons - Soluble in polar solvents - attraction weakens the lattice |
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What is the electronegativity?
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A measure of attraction of a bonded atom to the pair of electrons in a covalent bond
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List the levels of repulsion from highest to lowest
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1. Two lone pairs
2. Lone pair to Bonded pair 3. Two bonded pairs |
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Where does electronegativity occur?
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In covalent bonds
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What is a permanent dipole?
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The charge difference on an electronegative atom
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How is electronegativity effected by nuclear charge and atomic radius?
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- large nuclear charge
- small atomic radius - increased electronegativity |
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Order the most electronegative elements from most electronegative to least
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1. Flourine
2. Oxygen 3. Nitrogen 4. Chlorine 5. Bromine |
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How is electronegativity effected as you go along the period?
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- Nuclear charge increases
- Proton Number increases - Atomic radius decreases - Electronegativity increases |
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How is electronegativity effected as you go down the group?
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- Nuclear Charge increases
- Number of shells increases - Electron Shield increases - Atomic radius increases - Electronegativity decreases |
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What are the exceptions to the octet?
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- Boron can exist with an incomplete octet
- Group 5, Group 6 and Group 7 elements can expand the octet |
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What are the names of the shapes of molecules?
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- Tetrahedral
- Trigonal Planar - Octahedral - Pyramidal - Non-Linear - Linear |
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Describe the Tetrahedral Shape
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- 4 bonded pairs
- 0 lone pairs - angle = 109.5 |
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Describe the Trigonal Planar shape
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- 3 bonded pairs
- 0 lone pairs - angle = 120 |
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Describe the Octahedral shape
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- 6 bonded pairs
- 0 lone pairs - angle = 90 |
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Describe the Pyramidal shape
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- 3 bonded pairs
- 1 lone pair - angle = 107.8 |
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Describe the Non-Linear shape
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- 2 bonded pairs
- 2 lone pairs - angle = 104.5 |
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Describe the Linear shape
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- 2 double bonds
- 0 lone pairs - angle = 180 |
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What happens to the dipoles in a symmetrical molecule?
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The dipoles cancel each other out and become non-polar
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Name the types of intermolecular force in order of strength
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1. Van der Waals forces
2. Permanent dipole to dipole interaction 3. Hydrogen Bonding |
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What are Van Der Waals forces?
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When more electrons are at one side of the atom in one snap shot moment creating an instantaneous dipole which induces a dipole in a neighbouring atom and forms an attraction
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Where do Van Der Waals forces occur?
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In all molecules
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What is Permanent dipole-dipole interaction?
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When the permanent dipoles on 2 neighbouring polar molecules are attracted to each other
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What is different about Permanent dipole-dipole interaction and Van Der Waals forces?
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The Van Der Waals dipoles are temporary
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Define hydrogen bonding
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The strong dipole-dipole interaction between an electron deficient hydrogen ion on one molecule and the lone pair of electrons on a highly electronegative atom on another molecule.
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Which bonds experience hydrogen bonding?
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OH and NH bonds
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Compare the densities of ice and water and explain why.
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- Ice is less dense than water
- Hydrogen bonds in ice hold water molecule apart in an open lattice, decreasing density |
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Why does water have a high melting and boiling point?
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The strong Hydrogen Bonds on top of Van Der Waals forces are very strong and require a lot of energy to break
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What properties, other than high melting and boiling point, exists in water?
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High Surface Tension
High Viscosity |
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What is a sub-shell?
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A group of the same type of atomic orbitals within a shell
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Where do dipole-dipole interactions occur?
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In molecules with an electronegative element that creates a permanent dipole
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