Production And Uses Of Substances In Relation To Properties Flashcards
Periods, groups, properties,
How do you work out percentage yield?
Actual amount/possible amount*100
What did Dmitri Mendeleev do?
Arranged elements in atomic number (proton number)
Put elements with same properties together under each other
Look at patterns
Ionisation energy
What happens across a period?
Proton number increases therefore
Electronegativity increase therefore
Energy to remove an electron (work function) increases
What does work function mean?
The energy needed to give to an electron to remove it from the element
Ionisation energy- What happens down a group?
A new energy level is added therefore
Outer electrons are further away and more shielding therefore
Require less energy to remove an electron
What happens to ionsation energy across a period?
Across a period more electronegativity so more work function
What happens to atomic radius in periodic table?
Decreases with more protons but
increases with energy levels added
What happens to ionic radius in periodic table?
Same as atomic radius but
Cations are behind by one element
Anions are ahead one element
What happens to electronegativity in periodic table?
Add protons increases but
Gain shells decreases
What is electron affinity
It’s like electronegativity
What happens with M.P and B.P across periods in metals and why?
All metals have low electronegativity therefore electrons can dissociate from nucleus
Web of electrons/metallic bonds
Left to right it increases, cause increasing electronegativity, cause more protons
The web of bonds become stronger so more energy to break them
What happens with M.P and B.P across periods in metalloids (in the middle) and why?
Boron and carbon had high M.P and B.P due to large lattice structures
Lots of Colavent bonds with a hint of metallic
What happens with M.P and B.P across periods in the left side/gases and why?
Increasing electronegativity, tighter electron clouds which makes molecules smaller
This weakens London dispersion forces as they have to get closer to have an interaction between molecules
What does ductile mean?
Being able to turn it into a thin wire
What does the graph for ionisation energy look like?
It increases across periods and then decreases down a group so the graph goes up and then down and then up again across the period
What happens to melting and boiling point in metals across a periodic table?
Across a period it increases as electronegativity increases
Why do metalloids have high m.p and b.p
Metalloids have high m.p and b.p because of the strong bonds they form with other atoms
Carbon makes giant structures
Colavent bonds with a hint of metallic bonding
Why do non-metals have low m.p and b.p?
They make small molecules because Van Der Waals forces are weak
What is electron affinity?
The ability of nucleus to grab a passing electron e.g electronegativity
What happens to reactivity across groups
The first groups have high reactivity because it has low electronegativity
Transition metals have middle electronegativity so it can’t gain or lose an electron easily
Right groups (3 to 7) increases as high electronegativity
Noble gases (group 8) full outer shell so doesn’t react
What is the reaction formula of metal with water?
Metal + water —⟩ hydroxide + hydrogen
E.g
2Li + 2H2O —⟩ 2Li2O
What is the reaction formula of metal with oxygen?
Metal + oxygen —⟩ metal oxide
4 Li + O2 —⟩ 2Li2O
What is the reaction formula of metal with acid?
Metal + acid —⟩ metal salt + hydrogen
2Li + 2HCl. —⟩ 2LiCl + H2
Sulfate —⟩ Li sulfate+ H
What does salt mean?
Ionic bonding between metal and non metal
What is the reaction formula of metalloid with water?
Metalloid + water —⟩ no reaction
What is the reaction formula of metalloid with oxygen?
Metalloid + oxygen —⟩ metalloid dioxide
Carbon + oxygen —⟩ carbon dioxide
What is the reaction formula of metalloid with hydrochloric acid
Metalloid + hydrochloric acid —⟩ metalloid chloride + hydrogen
Carbon + hydrochloric acid —⟩ carbon chloride + hydrogen
Weak reaction
Carbon chloride decomposes as carbon doesn’t give or take electrons easily
What do non metals do with oxygen?
Make small molecules e.g NO2
Gases are held together by Van den Waals forces
What happens to reactivity down group 1 and why?
As you go down group 1 the electronegativity decreases as more energy levels are added,
so it’s easier for the atom to lose an electron
Therefore reactivity increases
What are the factors that reduce yield?
Incomplete reactions
Wasted chemicals
Hydration
Extraction
Side reactions
What does OIL RIG mean?
Oxidation
Is
Loss
Reduction
Is
Gain …. Of electrons
What is the oxidation state of all elements?
Zero, as the number of protons and electrons are the same
What is redox?
Where a reaction has both oxidation and reduction take place
What happens to ionic radius of cations across periods?
It decreases, it gets smaller but one element ahead of normal atomic radius
What does amphoteric mean?
A substance that can act as both an acid and a base
What are allotropes?
Allotropes refer to when an element forms different physical forms
e.g. graphite and diamond are allotropes of carbon
What is a half equation?
An equation that shows the loss or gain of electrons during a reaction
What does oxidation number mean
the number of electrons an element has lost or gain
this number can be positive or negative depending on how many electrons, the element has lost or gained
What are oxidising agent?
Substances that take electrons from other atoms or ions
Halogens are oxidising agents
Why are transition metals unreactive?
the electronegativity in metals is too weak to steal electrons from other atoms
and is too strong for the electrons to be lost to other elements
Why do metals have different oxidation states?
Metals have 4s and 3d electrons
Unpaired electrons can be removed easily therefore different oxidation states
Why can Manganese have oxidation states between +2 and +7
Because Mn can lose electrons in 4s and 3d orbitals and sub-shells
The electrons that are further away from nucleus and unpaired are easily loss
This means Mn can lose multiple electrons
What happens when you dissolve a metal oxide?
You get a alkaline solution and metal hydroxide
What happens when you dissolve a non-metal oxide?
You get a acid solution
Why do metals tarnish?
Metals react with oxygen in the air and form metal oxide
A piece of sodium is place into water
What would you observe?
The sodium would react with the water quite aggressively, it would fizz in the water
It would make a alkaline solution
