Chemistry Module 1 Bonding

Question 1

What is a bond?

Answer 1

The force of attraction between oppositely charged particles which can be intramolecular or intermolecular.

Question 2

What is valency?

Answer 2

This is the ability of an atom to form bonds. The number of electrons that must be lost, gained or shared when an atom bonds.

Question 3

What is a valence shell?

Answer 3

This is the outermost shell of an atom containing the highest energy orbitals.

Question 4

What is a valence electron?

Answer 4

These are the electrons found in the highest energy orbital of an atom that forms bonds.

Question 5

Why do atoms bond?(what does the electronic theory of valency state)

Answer 5

Atoms bond to obtain the most stable (lowest energy) electronic configuration by gaining, losing or sharing electrons.

Question 6

What do the physical properties of an element depend on?

Answer 6

It depends on the strength of the Forces of Attraction .

Question 7

What factors are impacted by substances which have stronver forces of attraction and in what way are they impacted? (5)

Answer 7

Melting point, Boiling point, Heat of Fusion, Vaporization and Density tend to be higher

Question 8

Does intramolecular or intermolecular forces affect the physical properties.

Answer 8

Intermolecular forces

Question 9

Which elements are in group 7?

Answer 9

Fluorine, Chlorine, Bromine and Iodine

Question 10

In group 7 is there an increase or decrease in the atomic radius down group 7?

Answer 10

There would be an increase as the number of electrons increase hence the number s
of shells also increase

Question 11

How is electronegativity impacted?

Answer 11

Electronegativity decreases down the group because as the atomic radius increases so does the atom. Any bonding pair gets furthed and further away from the nucleus of the halogen and therefore becomes less attracted towards it.

Question 12

What is metallic bonding?

Answer 12

The force of attraction between positive nuclei and the sea of electrons

Question 12

What are delocalized electrons?

Answer 12

They are electrons whuch are not associated with any particular atom or ion. They are free to move between the metal ions.

Question 12

What are the physical properties of metals?

Answer 12

They have high melting points, boiling points, heats of fusion, and vaporization and therefore are nonvolatile.

Question 12

What is meant by non-volatile?

Answer 12

The substance does not vaporizerapidly.

Question 12

Metals are generally solid except for?

Answer 12

Hg

Question 12

Why do metals have such factors?

Answer 12

They have string metallic bondswhich require a lot of energy to change the state

Question 13

Why are metals malleable and ductile?

Answer 13

The layers of the metal ions can slide over each other. The attractive forces between the metal ions and the electrons can still act in all directions. So when the layers slide, new bonds can easily form which leaves the metal in a different shape but still strong

Question 14

Why are metals good conductors of heat?

Answer 14

When heated kinetic energy is passed on through the system as particles vibrate more bumping other particles and transmitting energy . The delocalized electrons can pass on energy quickly as they move.

Question 15

Why are metals good electrical conductors?

Answer 15

When solid or molten, the negatively charged electrons move towards the positive potential when an electric current is applied to the metal.

Question 16

Why are metals insoluble in polar and non-polar solvents?

Answer 16

The non-specific nature of the metallic bond means the metals cannot form attractions either in polar or nonpolar solvents. But they can dissolve in other metals

Question 17

Why are metals shiny?

Answer 17

They possess a large number of molecular orbitals at a large number of energy levels. When light falls on the metals, electrons are promoted to higher energy levels. Hence light is emitted as these electrons return to their ground state.

Question 18

Ionic bonding is also known as?

Answer 18

Electrovalent bonding

Question 19

What is an ionic bond?

Answer 19

The force of attraction between two oppositely charged ions

Question 20

Are ionic bonds strong or weak?

Answer 20

There are very strong bonds

Question 21

Ionic bonding involves the interaction between which elements?

Answer 21

electrons from metals to nonmetals

Question 22

How does ionization energy affect the ionic bond?

Answer 22

If the ionization energy is lower it can easily lose electrons. If higher it would take more energy to lose electrons to form bonds between metals and non-metals.

Question 23

What is electron affinity?

Answer 23

This is the energy released when an electron is added to a neutral atom to form an anion. Energy change when 1 mole of gaseous electron is added to 1 mole of a gaseous atom to form 1 mole of gaseous anions

Question 24

Using A show an equation of electron affinity.

Answer 24

A(g)+1e- --> A^-(g) (electron affinity)

Question 25

Which electron affinity is exothermic and endothermic?

Answer 25

1st electron affinity is exothermic 2nd electron affinity and beyond is endothermic NB the more exothermic the easier it is to form an anion

Question 26

What is lattice energy?

Answer 26

The energy released when 1 mole of an ionic solid is formed from its gaseous ions

Question 27

How are solid ions organized?

Answer 27

They are organized in a solid ionic lattice of alternating cations and anions. The more exothermic the more stable the lattice energy, which in turn ensures the likelihood of a compound being formed

Question 28

What are the characteristics of an ionic bond?

Answer 28

one element must have Low ionization energy, the other must have a high negative electron affinity the compound being formed must have high exothermic lattice energy

Question 29

What are the physical properties of ionic compounds?

Answer 29

1. Giant ionic crystal lattices 2. High Melting and Boiling Points 3. High heat of fusion and vaporization 4. Brittle 5. Soluble in water and polar solvents 6. Conduct Electricity only in molten state

Question 30

Describe the ionic crystalline state of ionic compounds

Answer 30

The ions are organized in a 3-D-like lattice of alternating anions and cations. Anions surround cations and cations surround the anions. The electrostatic force between the anions and cations holds the structure together.

Question 31

Why do ionic compounds have high mp, bp, heat of fusion, and vaporization?

Answer 31

Ionic compounds contain strong ionic bonds. Due to these strong bonds in the lattice, it takes great energy to break them. This energy can be sourced in the form of heat. The stronger the bond the greater the amount of heat energy needed to break the bonds

Question 32

Ionic compounds in the molten state conduct electricity

Answer 32

When in the molten state the bonds in the lattice are broken and hence the ions are free to move around and when charged can carry electricity through them. When in the solid state they cant move hence why it isn't a good conductor.

Question 33

Why are ionic compounds brittle?

Answer 33

When a mechanical force is applied to an ionic compound, its lattice structure is dislocated. The anions are no longer, bonded to the cations and vice-versa. Instead, anions are paired with each other and cations with cations. This causes a repulsion causing the lattice to break down.

Question 34

Why are ionic compounds soluble in water?

Answer 34

The charges on the ions attract the dipoles on the water molecules. The formation of these interactions releases energy which is enough to cause detachment if ions from the lattice, resulting in the solid dissolving.