Structure And Bonding

Question 1

Will a positive ion be attracted to any negative ion?

Answer 1

Yes

Question 2

Is a sodium ion only bonded to the chlorine ion it’s donated its electron to in sodium chloride?

Answer 2

No

Question 3

Can a dosing atom only form one ionic bond because it only has one electron in its outer shell to donate?

Answer 3

No

Question 4

Is the reason a bond is formed between chloride and sodium atoms because an electron has been transferred between them?

Answer 4

No, it is due to the electrostatic forces of attraction between the oppositely charged ions.

Question 5

Is a chlorine ion attracted to one sodium ion by a bond, and the other by forces?

Answer 5

No

Question 6

Can a positive ion be bonded to ny neighbouring negative ions, if it is close enough?

Answer 6

Yes

Question 7

Can a negative ion be attracted to any positive ion?

Answer 7

Yes

Question 8

Is a chlorine ion only bonded to a sodium ion it accepted an electron from?

Answer 8

No

Question 9

Can a chlorine ion only form one ionic bond, because it can only accept one more electron in its outer shell?

Answer 9

No

Question 10

Is the reason a bond is formed between chlorine and sodium ions the opposite charges?

Answer 10

Yes

Question 11

Can a positive ion only be attracted to one negative ion?

Answer 11

No

Question 12

Are there no molecules in the sodium chloride lattice structure?

Answer 12

Yes

Question 13

The structure of ionic compounds

Answer 13

➢ Electrons are transferred when ionic compounds are
formed.
➢ Ionic compounds form giant ionic structures with ions
arranged in a regular 3D lattice.
➢ Ionic compounds are held together by strong ionic
bonds.

IONIC BOND: The strong electrostatic force of attraction between oppositely charged ions.

Question 14

Draw the structure of sodium chloride

Answer 14

N/a

Each sodium ion is surrounded by six chloride ions and each chloride is surrounded by six sodium ions.

Question 15

Properties of ionic compounds

Answer 15

All ionic compounds consist of huge lattices of alternating positive and negative ions arranged in a regular way. The lattice is held together by the strong attractions between the positively and negatively charged ions.

➢ Some common properties of ionic compounds.
• High melting and boiling points
• Brittle
• Often soluble in water
• Conduct electricity when molten or in solution, but not
when solid.

➢ Explain these properties with reference to the structure
of ionic compounds

Question 16

Why do ionic compounds have high melting points?

Answer 16

Ionic compounds are giant structures held together by strong electrostatic forces of attraction between oppositely charged ions which require a lot of energy to overcome.

Question 17

Why are ionic compounds hard and brittle?

Answer 17

They are stuck together in a large lattice structure

Question 18

Why are ionic compounds usually soluble in water?

Answer 18

As the ions have a stronger attraction to the water molecules than each other

Question 19

Why can ionic compounds conduct electricity when molten or in solution, but not solid?

Answer 19

When solid, the ions are in fixed positions and cannot move.

When molten or in solution, ions are free to move and carry an electric current.

Question 20

What are simple molecular structures?

Answer 20

Simple molecular structures are formed from only a few atoms. There are strong covalent bonds between the atoms within a molecule.

Examples of simple molecules are
water H2O carbon dioxide CO2 ammonia NH3
methane CH4
nitrogen N2 butane C4H10 oxygen O2

Question 21

Simple molecular structures forces

Answer 21

There must also be forces of attraction between one molecule and its neighbours; otherwise they would not come close enough together to be able to form a liquid or a
solid. These intermolecular forces are much weaker than the covalent bonds and vary in strength from one covalent substance to another.

Melting and boiling a substance which is made of simple molecules involves overcoming the weak intermolecular forces NOT breaking the covalent bonds.

Question 22

Properties of simple molecular substances

Answer 22

These substances have low melting points and boiling points because there are weak forces of attraction between the molecules which take very little energy to overcome. They tend to be gases e.g. carbon dioxide, liquids, e.g. water, or solids with low melting points e.g. iodine.

The larger the molecules, the stronger the forces of attractions between the molecules, so the higher the melting and boiling points. Hence chlorine is a gas at room temperature whereas iodine is a solid.

Simple molecular substances do not conduct electricity in any state because electrons held in covalent bonds so are not free to move.

Simple molecular substances tend to be insoluble in water (unless they react with it).

Question 23

What happens when you heat a crystalline structure?

Answer 23

The intermolecular forces that hold together the molecules in the structure aren’t strong enough to hold the molecules in a crystal, giving them energy through the heating process. There are now temporary attractions between the molecules, that are being broken and re-made all the time.

Question 24

What happens when you heat a liquid?

Answer 24

More heat makes the molecules move so fast that the attractions can’t hold them anymore, so the intermolecular attractions are completely broken, but the covalent bonds and still there. This is a gas.

Question 25

Giant covalent structures and their properties

Answer 25

There are some elements and compounds that consist of many hundreds of thousands of atoms joined by strong covalent bonds to form a single giant structure. These substances have high melting points and boiling points because there are many strong covalent bonds between the atoms which take lots of energy to break.

Question 26

Silicon (VI) oxide

Answer 26

It is a very well known compound in the forms of sand, quartz and flint. These are all very hard substances because silicon (VI) oxide has a giant covalent structure. Each silicon atom is covalently bonded to 4 oxygen atoms and each oxygen atom is bonded to 2 silicon atoms.

Question 27

Can covalent structures conduct electricity?

Answer 27

Most covalent compounds do not conduct electricity because they are composed of neutral molecules rather than charged particles, meaning there are no free ions or electrons to carry charge. They act as insulators, often existing as gases or liquids at room temperature.

Question 28

Are giant covalent structures soluble?

Answer 28

No, giant covalent structures are not soluble in water. They consist of millions of atoms held together by strong, rigid covalent bonds in a 3D lattice (e.g., diamond, silica) that water molecules cannot break. These structures are also generally insoluble in other solvents and typically have very high melting points.

Question 29

Why are giant ionic compounds soluble?

Answer 29

Many giant ionic compounds are soluble in water because polar water molecules attract and separate the ions within the crystal lattice. While they are generally considered soluble, solubility varies, and some ionic compounds. Why They Dissolve: Water is a polar solvent, meaning it has partial positive (hydrogen) and negative (oxygen) charges. These partial charges surround and pull apart the positive and negative ions, a process aided by hydration. Solubility Factors: Generally, the higher the charge density of the ions (e.g., 2+, 2- ions), the harder they are to pull apart, making them less likely to dissolve compared to +/compounds (like NaCl)

Question 30

Why is chlorine a gas at room temperature?

Answer 30

Chlorine (Cl(2)) is a gas at room temperature because it consists of small diatomic molecules held together by weak intermolecular forces. These weak forces require very little energy to overcome, resulting in a low boiling point of -34C, meaning it exists as a gas at typical room temperatures

Question 31

Buckminster fullerene

Answer 31

C(60) is a manmade structure, that is simple. It has a low melting and boiling point and can conduct electricity poorly. It can carry medicine/antidotes in blood to the target site.

Question 32

Why can graphite conduct electricity?

Answer 32

Graphite conducts electricity because each carbon atom is covalently bonded to only three others, leaving one "spare" electron per atom. These fourth valence electrons are delocalized, forming a "sea" of free electrons that can move across the planar layers and conduct electricity.