Bonding

Size of ionic substances

All parts of ionic substances have different sizes

Any atom containing Nh4

HAS A COORDINATE BOND ALREADY

CO2 and SO4 are have double bonds

How many bonding pair and lone pairs do noble gases have

Bonding pairs-4

2-lone pairs

Electronegativity

Relative ability of an atom to attract the pair of electrons to a covalent bond

Why is a C-Cl bond polar

Chlorine has a higher electronegativity than carbon

Why is a CCl4 molecule non polar

Symmettrical value determined from its bond angle

Draw a 3D diagram of barium oxide

Explain a 90 degree bond angle

All bond angels repel equally

Explain a 107 degree bond angle

Lone pair bond pair repulsion is greater than bond pair bond pair so bond angle reduced

Explain a 109.5 degree bond angle

Lone pair lone pair repel more than bond pair bond pair

So lp is far apart as possible

Which is more electronegative

O

N

O

Do inorganic ionic compounds always form giant structures

Yes

In what substances do covalent bonds break when it melts

Giant covalent structures

Silicon dioxide is an example of a giant covalent structure

What is the crystal structure of ionic substances

Simple molecular

Which molecule is the most polar?

Bromoethane

Dibromoethane

Tribromoethane

Tetrabromoethane

Tetrabromoethane

How does electronegativity change across a period

Increases across a period

CH4 -can it form a covalent bond

Can’t form a covalent bond

8 electrons around it no spaces available go to take lone pairs or give

Draw structural formula of it to determine this

Number of sticks multiplied by 2 is the number of electrons there are

Can BH3 form coordinate bond and how

Yes

No lone pairs

6 electrons only so can take 2

Can CH4 form coordinate bonds?

8e-

No space for e- to come

No lone pairs can come

Can’t form a coordinate bond

Can NH3 form a coordinate bond?

Yes

8 electrons

Can give 2 electrons as a lone pair

Can H2O form a coordinate bond

4e-

2 lone pairs of electrons

Can give electrons away

When can you not transfer lone electrons to something

When it already has a pair of lone electrons

What does the group number show about bonds

The group number is the number of valence electrons and how many bonds something can make

Which substance does not have any bond angles of 120

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Benzene

Cyclohexane

Boron trifluoride

Cyclohexane

Benzene does have 120

How do you know if an element can accept an electron pair in a dative coordinate bond

It only has 6 electrons in its outer shell

This could be as a compound or element so it has a space fr another 2

What reaction can a result in an overall change in shape around a carbon atom

• oxidation of propanol with acidifies potassium dichromate

• Polymerisation of tetrafluoethene

• Reaction of bromoethane with an excess of concentrates ammonia

• Reaction of methane with an excess of chlorine in ultraviolet radiation

Polymerisation of tetrafluoethene

Which substance has more electrons delocalisation

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Iodine

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1 delocalised electron per 3 carbon atoms bonded

What forces or bonds are broken when water is vaporised

Intermolecular forces are overcome

What is not responsible fro conducting electricity

Lone pair of electrons.

Which substance has no delocalised electrons

Methylbenzene

Polypropene

Polypropene doesnt’ have any delocalised electrons 3

Long chain of atoms

Which pair of reagents reacts to form a tetrahedral complex

How do you know if a compound will form a dative covalent bond

The main atom will need two more electrons as it will only have 6 electrons already

What factors affect metallic bonding

Number of valence electrons

Ionic charge

Atom size

How does the number of valence electrons affect the strength of a metallic bond

The more valence electrons there are then stronger the metallic bond

Which element has the lowest melting point

Sodium

Magnesium and potassium both have more electrons in the outer shell so stronger metallic bond high melting point

Sodium has less electrons in its shells so smaller atomic radius and greater attraction to electrons so harder to overcome needing more energy and a higher melting point

How are ionic compounds formed

Transfer of electrons from a metal to a non metal

Metal atoms …….electrons to become positive ions

Lose

Non metal atoms …… electrons to become negative

Gain

Positive Ions are called

Cations

Negative ions are called

Anions

Ionic bond

Electrostatic force of attraction between oppositely charged ions

What shape do ionic solids take

Ionic lattice structure

Lattice

Regular repeated three dimensional framework of atoms molecules or crystalline structure

What is the configuration of the ionic lattice of NaCl

6.6 configuration

Forms

What causes the crystalline nature of ionic compounds

Regular pattern of ions

Relationship between the size of the ions and the charge and strength of the ionic bond

Smaller the ions

Higher charge on ions

Stronger the ionic bond

Positive Ions are generally ….than the atoms from which they are formed

Smaller

Negative ions are generally …….than the parent atom

Larger

Why are positive ions smaller than the atoms they are made of

Metal atoms lose electrons from outer energy level so ion has an electron configuration with one less energy level occupied

Nuclear charge increases so electrons are pulled closer to the nucleus

Thus smaller atomic radius

Why are negative ions larger than the parent atom

Repulsion between electrons moves them further apart from each other

Nuclear charge decreases as there are more electrons with the same number of protons

Properties of ionic compounds

Lattice structure

Conduct as molten or aqueous

high melting and boiling point or solid at room temperature

Formula for surfate ion

SO4 ²-

Formula for nitrate ion

NO3^-

Formula of hydroxide ion

OH^-

Formula of carbonate ions

CO3²-

Formula of hydrogen carbonate ion

HCO3^-

Formula of ammonium ion

NH4^+

Covalent bond

One or more shared pair of electrons

Where are covalent bonds found

Molecular elements

Macromolecular elements

Molecular ions

In what do covalent bonds form

Non metals only

Boron trifluoride how does it form its covalent bonds-diagram

How does beryllium chloride from covalent bonds

How does methane form covalent bonds

How does ammonia form covalent bonds diagram

How does water form covalent bonds

How does sulfur hexafluoride

How does carbon dioxide form covalent bonds

Coordinate bond

Shared pair of electrons with both electrons supplied by one atom

Example of a coordinate bond

NH4^+

What colour are the fumes of ammonium chloride

White fumes

What does hydrochloride acid and ammonia solution react to give

Ammonium chloride

Formula for hydronium ion

H3O^+

What determines how many lone pair of electrons there are

The amount of empty orbital there are after having covalently bonded to something before

Arrangement of particles in a solid

Close together regular arrangement

Metallic structure of metals explain

Positive metal ions in a sea of delocalised electrons

Metallic bond

Electrostatic force of attraction between delocalised electrons and the positive metal ions in a lattice

Properties of metals

Conduct electricity

Conduct heat

Ductile and malleable

Hugh densities

High melting points s

Why can metals conduct electricity

Delocalised electrons move through the structure and carry charge

How can metals conduct heat

Delocalised electrons enable heat energy to be passed through the metal

Why are metals ductile and malleable

Layers can slide over each other without disrupting bonding

Why do metals have high densities

Positive ions are packed tightly together so density is high

Why does the melting point increase in some elements

Attraction between smaller positive ions and the negative delocalised electrons is greater

Name the two main types of covalent substances

Molecular -simple covalent

Macromolecular -giant covalent

How do you know if a substance is simple molecular

Exist as single molecules-can’t become anything else with themselves only

Name some simple molecular substances

Iodine

Ice

How does iodine form a crystalline structure

Large iodine molecules pack together into a regular arrangement

How does ice from a crystalline structure

Molecules of water arranged in a regular arrangement

Properties of molecular covalent crystals

• low melting points

• Brittle

• Don’t conduct electricity

Why are molecular covalent crystals brittle

Don’t have strong bonds holding them together

Why can’t molecular covalent crystals conduct electricity

No charged particles to carry charge through the structure

What type of substances can form Macromolecular structures

Non metallic elements and compounds

Allotropes of carbon name

That u need to know

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Diamond

Properties of diamond

Hardest

High melting point

Doesn’t conduct heat or electricity

Why does diamond have a high melting point

Strong covalent bonds that require lots of energy to overcome

Why does diamond not conduct heat or electricity

No delocalised electrons that can move through the structure

Why is diamond hard

Each carbon is bonded to 4 others in a tetrahedral arrangement

Use of diamond

Cutting tools

Graphite properties

Conducts electricity

High melting point

Slippery

Why can graphite conduct electricity

One delocalised electron per carbon atom that can move through the structure and conduct electricity