Chemistry - Bonding

what is ionic bonding?

ionic bonding involves electrostatic attraction between oppositely charged ions in a lattice.

what is the formula of a sulfate ion?

SO₄²-

what is the formula of a hydroxide ion?

OH-

what is the formula of a nitrate ion?

NO3-

what is the formula of a carbonate ion?

CO32-

what is the formula of an ammonium ion?

NH4+

what is a single covalent bond?

it contains a shared pair of electrons, multiple covalent bonds contain multiple pairs.

what does ionic bonding involve?

it involves the transfer of electrons from a metallic element to a non-metallic element.

metals lose electrons forming...

positive ions (cations)

non-metals gain electrons forming...

negative ions (anions)

what is the ionic bond?

the electrostatic force of attraction between the oppositely charged ions which occurs in all directions.

why do ionic compounds have high melting points?

Because the electrostatic force is very strong and so requires a large amount of energy to overcome them.

what are the features of a giant ionic structure?

1. regular structure
2. cubic shape
3. Giant repeating pattern

why are most ionic compounds soluable?

as water molecules are polar they can attract the negative and positive ions and break up the structure.

when do ionic compounds conduct electricity?

when molten or dissolved as the ions are free to move around and carry a charge throughout the structure.

what is covalent bonding?

it is the sharing of outer electrons between two non-metals in order to gain a full outer shell

where is the electrostatic force of attraction in a covalent bond?

between the negative outer electrons and the positive nucleus.

what is a dative or a co-ordinate covalent bond?

where one atom donates 2 electrons to an atom or ion to form a bond

give 2 examples of giant covalent structures

graphite and diamond

why does graphite have a high melting point?

it has lots of strong covalent bonds

why do graphite layers slide?

they slide as there are weak intermolecular forces between the layers.

can graphite conduct electricity?

Yes, because it has a delocalised electrons between the layers that can carry a charge throughout the structure.

why does graphite have a low density?

the layers are far apart in comparison to covalent bond length.

why is graphite insoluable?

the covalent bonds are too strong to break.

describe the bonding in diamond.

Each carbon is bonded to 4 other carbon atoms.

why is diamond a good conductor of heat?

the tightly packed rigid structure allows heat to conduct well in diamonds.

why does diamond have a high melting point?

it has lots of strong covalent bonds - like graphite which require a lot of energy to be overcome.

does diamond conduct electricity?

no, it has no delocalised electrons

the smaller the atom..

the closer the nucleus is to the shared electrons, meaning greater electronegativity

the larger the nuclear charge..

the greater the electronegativity

what makes a covalent bond polar?

where two atoms of different electronegativity are bonded together.

what is metallic bonding?

metallic bonding consists of a lattice of positively charged metal ions in a sea of delocalised electrons.

what does metallic bonding produce?

A very strong electrostatic force of attraction between positive metal ions and negative electrons.

what does the number of delocalised electrons depend on?

how many electrons have been lost by each metal atom.

are metals good conductors of electricity?

yes, the delocalised electrons that can move throughout the structure and can carry a charge.

why are metals good conductors of heat?

thermal energy is spread quickly due to the closely packed metal ions.

what does the strength of a metal depend on?

1. the charge on the ion - the greater the charge the greater the number of delocalised electrons and the stronger the electrostatic attraction between the positive ions and the electrons.
2. the size of the ion, the smaller the ion, the stronger the bond.

why are metals malleable?

since the layers of positive metal ions can slide over each other.

why do metals have high melting and boiling points?

they have giant structures.

why are ionic compounds brittle?

When the layers of alternating charges are distorted, like charges repel, breaking apart the lattice into fragments

what can be used to explain the increasing boiling points of the halogens whilst going down the group?

the increasing boiling points of the halogens as you go down the group is due to the increasing number of electrons in the bigger molecules, increasing the strength of the VaW forces.