topic 2 bonding and structure

Ionic bonding definition

The electrostatic attraction between oppositely charged ions

When are ions formed

when atoms gain or lose electrons for full outer shell

Metals lose electrons to form what?

positive ions / cations

Non metals gain election to form what

Negative ion and anion

Where does ionic bonding usually occur

Metals + non metals

Within complexions what bonds hold the atoms inside ions.

Covalent bond

4 mark: mg chloride contains magnesium-ions chloïdeions describe in terms of elections what happens when a magnesium's atom reacts with chlorine atoms to produce magnesium chloride

One magnesium atom loses 2 electrons 2 chlorine atom each gains 1 electron form magnesium. One magnesium atom reacts with 2 chlorine atoms to form magnesium ion and chloride ions

What bonding in regular polyatomic ion

Covalent

What are polyatomic ion

Ions containing more than 1 atom

What is an ionic compound overall

Neutral as total positive charge equals negative charge

How is formula of ionic compound written

Simplest whole number ratio of ions , positive cation written first then anion neg next

When are brackets used

If more than 1 polyatomic ion

What are physical properties of ionic compound

High melting point and boiling point and can conduct electricity when molten or aqueous is soluble in water

What's is ionic bond

Electrostatic force of attraction between opposite charges ion.

Properties of ionic compounds

Ionic compound arranged in giant ionic lattices with electrostatic forces

Why does ionic bond have high melting point and boiling point

Because strong electrostatic force of attraction between ions so there's lots of energy to overcome attraction . If ions have greater ionic charge . Melting points are much higher

How can ionic compounds conduct electricity

Molten or in aqueous as ions are free to move and carry charge throughout structure

Talk about solubility in ionic compounds

Many ionic compound is dissolve in water. Water molecule attract the ions strongly enough to separate them from ionic lattice

What complex ions do u need to know

-OH = hydroxyl

NO*-nitrate

SO4*2-=sulphate

CO3*2- carbonate

NH4- AMMONIUM not complex

PO4*3- phosphate

HCO*3-= bicarbonate

Give oxidation reaction equation

Substance + oxygen = oxide

Give 2 displacement equation

Metal + water = >metal hydroxide + hydrogen

Metal + acid = >salt + hydrogen

give 5 examples neutralization equation

Metal oxide + acid = >water + salt

Metal hydroxide + acid = >water + salt

Carbonate + acid = >carbon dioxide + salt

Hydrogen carbonate + acid= >salt + water + carbon dioxide

Ammonia+ acid =>ammonium

Thermal decomposition equation

metal carbonate --> metal oxide + carbon dioxide

Sulfuric acid symbol

H2SO4

Nitric acid symbol

HNO3

Hydroxide symbol

OH-

solubility rules

all alkali metals and ammonium salts are soluble

all nitrates chlorates and perchlorates are soluble

all silver , lead and mercury salts are insoluble- apart from silver nitrate

all chlorides bromides and iodides are soluble

all carbonates oxides sulfides hydroxides phosphates chromates and sulfites are insoluble

all sulfates are soluble

grp 1 hydroxides soluble and some grp2 hydroxides soluble

what are ionic equation

shows chemical reaction using only ions that are acctually involved in reaction

only split aq ionic compounds into ions . dont split solid liquid or gases or insoluble precipitate into ions .

remove spectator ions

what are spectator ions

ions that do not change during reaction are called spectator ions are are left out

how to identify monatomic substances

super low mp/bp does not conduct electricity in any state can be insoluble in aq

how to identify metallic bonds/substances

conduct electricity as solid and liquid can be insoluble in aq or react w water

how to identify covalent giant

super high bp/mp cant conduct electricity n sometimes soluble in aq

how to spot simple molecular substances.

low mp/bp cant conduct electricity and can be insoluble in aq

describe metallic bonding

electrostatic forces of attraction between metal cations and delocalised electron within a metal

why can metals conduct electricity and heat

contain delocalised electron which carry charge through structure

why does metals have high mp and bp

strong forces of electrostatic attraction between cations and delocalised electrons

which require lots of energy to break

why are metals malleable

easily hammered and bent into shape as layers of metals ions are uniform and can easily slide over each other

why alloys r stronger than pure metal

alloys r different sized atoms as they are a mixture of diff element

diff sized atoms create layers to distort

so layers can not slide

why is mg higher m than sodium

mg has smaller ionic radius and nuclear charge is higher so attraction between nucleus and valence electron is stronger and shielding is the same

explain trend in mp and bp in group 1

mp/bp decrease

as you go down group shielding increases so electrons easier to lose as attraction between nucleus and outer electron decreases

so ionic radius increases as distance increases

less energy needed to overcome attraction and break metallic bonds

examples of giant metallic

Na Mg Al

what is the melting temp for giant metallic

generally increases across period 3 as metallic bonding strengthens

giant covalent example element

Si

simple molecular atomic eg

cl2 S8 P4 Ar

why is simple molecular low temp

low as weak london forces

at room temp n pressure how much is 1 mol of ANY gas occupy-conc

24dm³

how to work out moles w conc

n= vc

pressure measured in

Pa -pascals

volume unit in ideal gas equation

m³

what is gas constant in ideal gas equation R

8.31 Jmol^-1 K^-1

temp unit ideal gas equation

temp in kelvin

dm³ to m³ conversion

1×10^-3

cm³ to m³

1× 10^-6

convert degrees to K

add 273

how to use molar volume to work out volume

V=nx24dm³

what properties impact high mp and bp

charge of ion

size of ion-ionic radius

explain why ionic compounds such as sodium chloride have brittle crsytals

An applied force causes layers of ions to slide / shift.

Ions of the same charge are brought next to each other

The resulting electrostatic repulsion forces the layers apart, causing the crystal to shatter.

how does electrolysis enable an electrical current to flow around external circuit

Negative ions losing electrons (oxidation) at the positive anode.

Positive ions gaining electrons (reduction) at the negative cathode

The movement/flow of these electrons through the wires/external circuit.

why sodium chloride dissolve in water and not hexane

water is polar solvent and attracts positive and negative ion separating them from ionic lattice

hexane organic solvent non polar cannot attract less strongly enough to dissolve sodium chloride.

why going down a group ionic radius gets smaller

positive ions down a group are isoelectronic

number protons increase and pull more toward centre of ion so ionic radii falls

negative ions the same with extra layer of electrons

which increase repulsion in outershell

outer electron push further apart from nucleus cause electron cloud to expand

why is NaCl higher boiling point than KCl

both have same ionic charge but Na has smaller ionicn radius as has less shielding so greater electrostatic attraction between Na +and Cl -ion

equation of concentration mass

Cm=m/V Cm=Mr x c

what is titration

analytical technique used to determine unknown concentration of a solution by reacting it with a solution of known concentration

what is covalent bond

electrostatic attraction between 2 nuclei and shared pair of electrons between them. between nonmetals and nonmetals

which period can fit more than 8 electron in their outer shell and why

period 3 as they have a 3d subshell

which 2 elements can hold less than 8 e- in outershell and why

boron and beryllium -after bonding as they are electron deficient compound

what is co-ordinate bond

dative covalent bond - where both the electrons come from same species

how are coordinate and dative bonds drawn

with arrows to show the direction electrons are donated so electron deficient atom can be filled

after co-ordinate bonds are formed what are they

identical to covalent bonds

after drawing diagrams to show formation of co-ordinate bond what statement do you write

lone pair from X (ion) is donated to Y of compound.

what is bond length

distance between nuclei of 2 covalently bonded atoms

what is bond energy

energy required to break 1 mole of particular covalent bond in gaseous state . units of kJmol-1.

why does bond length increase down halogen group

atomic radius increases

each successive hallogen atom has more electron shell/greater shielding

larger halogen atom have greater atomic radius so shared e- is further from both nuclei so form longer weak bond.

weaker electrostatic attraction between nuclei and shared pair e-

bond energy trend down a group

decreases

as atomic radius increases bonding pair further from nucleus as greater shielding

weak electrostatic forces between nuclei and shared electron

so require little amount of energy to break bond.

how is 2 hydrogen atom held together by covalent bond

2 hydrogen nuclei attracted to shared pair of electron

difference of lone and and bonding pairs of electrons

lone pairs belongs to 1 atom only and not used in chemical bond aka non bonding pair

bonding pair - pair of electrons that is shared between 2atoms to form covalent bond

what determines shape of molecules and ion and explain

bonding pairs and lone pairs

electron pairs will repel each other to be as far as possible to minimise repulsion

5 fundamental shape

linear

trigonal planar

tetrahedral

trigonal bipyramidal

octahedral

what are angles and bonds of the 5 fundamental shape

linear-- 180’ 2 pair

trigonal planar-120’ 3 pair

tetrahedral-109.5’ 4 pair

trigonal bipyramidal - 90’ and 120’- 5 pair

octachedral-90’ - 6 pairs

what is shape and angle of 2 e-pair with 2 bonding pair and 0lone pair

linear-180’

shape and angle of 3 e- pairs w 3 bonding pairs and 0 lone pairs

trigonal planar-120’

shape n angel 3 e- pairs 2 bonding 1 lone

bent/v shape118’

shape and angel 4e- 4 bonding 0 lone

tetrahedral 109.5

shape and angel 4e- pair 3 bonding 1 lone

trigonal pyramidal 107’

shape angel of 4e- pairs 2bonding and 2 lone pairs

bent/Vshape 104.5’

shape and angel 5 e- pair 5 bonding 0 lone

trigonal bipyramidal 90’ and 120’

shape n angel of 5 e-pair 4 bonding 1 lone

trigonal pyramidal/see saw 119’ and 89’

shape and angel of 5 e-pair 3 bonding 2 lone

trigonal planar /T shape 120’ or 89’

shape n angel of 6e-pair 6 bonding 0 lone

octahedral 90’

shape and angel 6 pair 5 bonding 1 lone

square pyramid 89’

shape and angel of 6 pair e- 4 bonding pair 2 lone

square planar 90’

describe repulsion between lone pair and bonding pair

lone pair and lone pair greater repulsion than any other bonding

lone pair and bonding pair repulsion f=greater than bonding and bonding

how much degrees does it decrease if theres lone pair

2.5

when deducing shape what 2 statements do u write

electron pairs repel each other to be far apart as possible to minimise repulsion

then pairing repulsion comparison and if it decreases angel.