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How many electrons can an s subshell hold?
2
How many electrons can a p subshell hold?
6
How many electrons can a d subshell hold?
10
Which subshells are available in the first energy level?
s
Which subshells are available in the second energy level?
s and p
Which subshells are available in the third energy level?
s, p and d
What is Hund's rule?
Orbitals must all be singly filled before they can be doubly occupied
Which elements do not fill the 4s subshell before the 3d subshell?
Copper and chromium
Define the term ionic bond
The electrostatic attraction between oppositely charged ions
What is the charge of an ion from group 1?
+1
What is the charge of an ion from group 2?
+2
What is the charge of an ion from group 6?
-2
What is the charge of an ion from group 7?
-1
Explain how atoms of sodium react with atoms of chlorine
Na loses its 2s1 electron gaining a +ve charge.
Cl gains an electron in the 3p subshell gaining a -ve charge.
The opposite charges attract to form NaCl
Why do ionic bonds have such high melting points?
Each +ve ion is surrounded by 6 -ve ions and vice versa.
Strong electrostatic attraction in every direction.
Requires a large amount of energy to break
State two factors that affect the strength of an ionic bond
Size of ion and charge on ion
When can ionic substances conduct electricity?
When molten or in aqueous solution
Describe the properties of ionic compounds
Conduct electricity when molten or aqueous solution
High melting/boiling points
Usually soluble in water
Define the term covalent bond
A shared pair of electrons
Which metals lose electrons from the 4s subshell before the 3d subshell?
Transition metals
Why do metals have such high melting points?
Strong force of attraction between positive ions and delocalised electrons. This requires a large amount of energy to overcome.
State the two factors that affect the strength of metallic bonding
Size of ion
Charge of ion
Explain how the charge on metal ions affects the strength of the metallic bond
The larger the +ve charge the greater the attraction between the nucleus and the delocalised electrons
Explain how the size of the metal ions affects the strength of the metallic bond
The smaller the +ve ion the closer the nucleus is to the delocalised electrons creating a greater attraction
Explain why metals conduct electricity
The delocalised electrons 'carry' charge. Current flows because of this.
Explain why metals conduct heat
Particles are paced tightly so kinetic energy is passed from ion to ion. The delocalised electrons also enable heat to be passed.
Explain why metals are ductile and malleable
The lattice structure allows layers of metal ions to slide over each other without disrupting bonding
Name the 3 forces between molecules
Van der Waals
Permanent dipole-dipole
Hydrogen bonds
Order the 3 forces between molecules in order of strongest to weakest
Hydrogen bonds
Permanent dipole-dipole
Van der waals
How are Van der Waal's forces formed?
Electrons move to one side, caused temporary dipole. This induces a temporary dipole in neighbouring molecules. Attraction occurs between oppositely charged dipoles
In what molecules do Van der Waal's forces exist?
Non-polar molecules
How are permanent dipole-dipole forces formed?
Permanent dipole in one molecule attracts oppositely charged permanent dipole in neighbouring molecule
In which molecules do permanent dipole-dipole forces exist?
Polar molecules
Which elements must be present for hydrogen bonds to exist?
Hydrogen and either nitrogen, oxygen or fluorine
What is meant by the term displacement?
When a more reactive element takes the place of a less reactive element in a compound
State the equation for determining moles
Moles = mass ÷ relative atomic mass (molar mass)
Define the term Avogadro's Constant
The number of atoms in a mole of a given substance. Quoted as 6.02x10^23
Define the term relative atomic mass
The average mass of an atom of an element relative to 1/12th the relative atomic mass of Carbon12
Define the term relative molecular mass
The average mass of a molecule relative to 1/12th the relative atomic mass of Carbon12
What does this number represent? 6.02x10^23
The number of particles in a mole. Commonly called Avogadro's Constant
What is the equation for calculating % yield?
% yield = (actual yield ÷ theoretical yield) x 100
What groups are included in the 's' block of the periodic table?
Groups 1 and 2
What part of the periodic table is known as the 'd' block?
Transition metals
Which groups are in the 'p' block of the periodic table?
3, 4, 5, 6 and 7
What is a group on the periodic table?
A vertical column
What is a period on the periodic table?
A horizontal row
Define the term first ionisation energy
The energy required to remove the outermost electron from one mole of gaseous atoms to produce one mole of gaseous +1 ions
Define the term atomic radius
The distance between the nucleus of an atom and the outermost electron
Define the term electronegativity
A measure of how well an atom attracts a bonding pair of electrons in a covalent bond
Define the term malleability
How easily a material can be hammered into shape
Define the term ductility
How easily a material can be drawn into wires
Describe the trend in atomic radius down any group
Atomic radius increases
Explain the trend in atomic radius down any group
Higher energy levels are filled. The orbitals in higher energy levels are further from the nucleus
Describe the trend in first ionisation energy down groups 1 and 2
First ionisation energy decreases
Increased electron shielding
Greater atomic radius
Smaller attraction to +ve nucleus:
SO electron is easier to remove requiring less energy
Describe the trend in melting points down groups 1 and 2
Melting point decreases
Explain the trend in melting points down groups 1 and 2
Strength of metallic bond is weaker due to greater atomic radius decreasing attraction between +ve nucleus and delocalised electrons
Describe the change in state as you go down group 7
The trend is they become more solid (i.e. fluorine is a gas, bromine is a liquid and iodine is a solid)
Describe the change in colour as you go down group 7
They become darker as you go down the group
Describe the trend in electronegativity down group 7
Electronegativity decreases down the group
Explain the trend in electronegativity down group 7
Greater distance between nucleus and bonding electrons
Greater electron shielding
Decreases attraction between nucleus and electron
Describe the trend in melting point down group 7
Melting point increases down the group
Explain the trend in melting point down group 7
Atomic radius increases
Stronger Van der Waal's forces
More energy needed to overcome the intermolecular forces
Describe the trend in atomic radius across a period
Atomic radius decreases
Explain the trend in atomic radius across a period
Greater nuclear charge (more protons)
Same number of electron shells
Same amount of electron shielding
Describe the trend in electronegativity across a period
Electronegativity increases across a period
Explain the trend in electronegativity across a period
Same amount of electron shielding
Greater number of protons
More attraction between nucleus and bonding pair of electrons
Describe the trend in melting point across a period
Melting point increases across the metals and then decreases throughout the non-metals
Explain the trend in melting point across a period
Metallic bonding gets stronger across the period. All other intermolecular forces are weaker than this and therefore easier to break
Why does the group 3 element have a lower first ionisation energy than the group 2 element
Electron taken from p subshell rather than s subshell so is further from the nucleus. Less energy is needed to remove the electron.
Why does the group 6 element have a lower first ionisation energy than the group 5 element
Electron is taken from a paired orbital rather than a singly occupied orbital. Electron repulsion between the pair reduces the energy needed.
Define the term displacement
When a more reactive element takes the place of a less reactive element in a molecule
Describe the trend in reactivity down group 1
They become more reactive down the group
Define the term reduction
Reduction is gain of electrons
Define the term oxidation
Oxidation is loss of electrons
Define the term reducing agent
A reducing agent is something that loses electrons
Define the term oxidising agent
An oxidising agent is something that gains electrons
What oxidation state do group 1 metals have?
+1
What oxidation state to group 2 metals have?
+2
What oxidation state do group 6 elements have?
-2
What oxidation state do group 7 elements have?
-1
What is the overall oxidation state of a molecule?
0
What is the overall oxidation state of a simple ion?
The charge on the ion
What is the overall oxidation state of a molecular ion?
The charge on the ion
What is the most common oxidation state of oxygen (with the exception of peroxides)?
-2
What is the overall oxidation state of an element?
0
In a compound containing only two elements which will have the negative oxidation state?
The more electronegative element
What is the oxidation state of hydrogen (except for in hydrides)?
+1
Is an atom oxidised or reduced if its oxidation number decreases?
Reduced
