Chemical bonding

Question 1

What is an ion?

Answer 1

An ion is an electrically charged atom or group of atoms formed by the loss or gain of electrons.

Question 2

Why does an atom lose or gain electrons?

Answer 2

An atom loses or gains electrons to become more stable. - To have a full outer shell of electrons (8 valence electrons) which is more stable arrangement of electrons.

Question 3

What is the electronic configuration of an ion?

Answer 3

The electronic configuration of an ion will be the same as that of a noble gas. - Full outer shells.

Question 4

Do metals lose or gain electrons?

Answer 4

Metals (all) lose electrons to other atoms to become positively charged ions.

Question 5

Do non-metals lose or gain electrons?

Answer 5

Non-metals gain electrons from other atoms to become negatively charged ions.

Question 6

What are positively charged ions known as?

Answer 6

Positively charged ions are known as cations.

Question 7

What are negatively charged ions known as?

Answer 7

Negatively charged ions are known as anions.

Question 8

What compounds is ionic bonding between?

Answer 8

Ionic bonding is between metals and non-metals. Ionic compounds are formed when metal atoms react with non-metal atoms.

Question 9

Explain the formation of ionic bonds.

Answer 9

Ionic bonds occur when metal atoms lose their outer electrons which the non-metal electron atoms gain to form positive and negative ions. The positive and negative ions are held together by strong electrostatic forces of attraction between opposite charges. This force of attraction is known as an ionic bond and they hold ionic compounds together.

Question 10

What is the lattice structure of ionic compounds?

Answer 10

Ionic compounds have a giant lattice structure.

Question 11

What is a lattice structure?

Answer 11

A lattice structure refers to the arrangement of the atoms of a substance in 3D space.

Question 12

How are atoms arranged in a lattice structure?

Answer 12

In a lattice structure, atoms are arranged in an ordered and repeating pattern. The lattices formed by ionic compounds consist of a regular arrangement of alternating positive and negative ions.

Question 13

What are the properties of ionic compounds?

Answer 13

Ionic compounds tend to
*Tend to be a solid
*They have high melting milting and boiling points
*Ionic compounds are good conductors of electricity in the molten state or in solution
*They are poor conductors in the solid state

Question 14

Why do ionic compounds have high melting and boiling points?

Answer 14

Ionic compounds have high melting and boiling points due to the presence of strong electrostatic forces acting between the oppositely charged ions. These forces act in all directs and a lot of energy is required to overcome them.

Question 15

Why are ionic compounds when in their molten state or in solution good conductors?

Answer 15

Ionic compounds are good conductors of electricity in the molten state or in solution as they have ions that can move and carry a charge.

Question 16

Why are ionic compounds poor conductors when they are in the solid state?

Answer 16

Ionic compounds are poor conductors when they are in the solid state because the ions are in fixed positions within the lattice and are unable to move.

Question 17

What do non-metallic elements form?

Answer 17

Non-metallic elements form simple molecules with covalent bonds between atoms.

Question 18

When are covalent compounds formed?

Answer 18

Covalent compounds are formed when pairs of electrons are shared between atoms.

Question 19

What elements participate in covalent bonding?

Answer 19

Only NON-METAL ELEMENTS participate in covalent bonding.

Question 20

Why does covalent bonding occur?

Answer 20

Covalent bonding is when each atom gains a full outer shell of electrons, giving them a noble gas electronic configuration. This is to gain a stable arrangement of electrons.

Question 21

What are molecules?

Answer 21

Molecules are when two or more atoms are covalently bonded together.

Question 22

What are simple molecules?

Answer 22

Simple molecules exist in which two adjacent atoms share one pair of electrons. They form a single covalent bond.

Question 23

What is a double bond?

Answer 23

A double bond is when two adjacent atoms share two pairs of electrons, causing two covalent bonds to form.

Question 24

What is a triple bond?

Answer 24

A triple bond is when two adjacent atoms share three pairs of electrons, causing three covalent bonds to form.

Question 25

What are the properties of Simple Molecular Compounds?

Answer 25

The properties of simple molecular compounds are:
*Small molecules are compounds made up of molecules that contain just a few atoms covalently bonded together
*They have low melting and boiling points so covalent compounds are usually liquids or gases at room temps
*As the molecules increase in size, the melting and boiling points generally increase
*Small molecules have poor electrical conductivity

Question 26

Why do simple molecular compounds have low melting and boiling points?

Answer 26

Simple molecular compounds have low melting and boiling points as there are only weak intermolecular forces acting between the molecules. The forces are very weak, so not a lot of energy is needed to overcome them. As the molecules increase in size, the intermolecular forces also increase as there and now more electrons available. This causes the melting and boiling points to increase.

Question 27

What is a single covalent bond?

Answer 27

A single covalent bond is the sharing of pairs of electrons leading to the noble gas electronic configuration.
Such as H2, Cl2, H2O, CH4, NH3 and HCl

Question 28

What is strong and what is weak in covalent bonds?

Answer 28

The bonds between within the molecules are strong, but the intermolecular forces are weak.

Question 29

What are the differences between ionic and covalent compounds related to solubility?

Answer 29

Ionic compounds are soluble in water but insoluble in organic compounds (compounds that contain carbon). They are soluble in water because the water is able to separate the ions and keep them in water. Covalent compounds are insoluble in water with some exceptions such as sugar and amino acids.

Question 30

What are the differences between ionic and covalent compounds related to electrical conductivity ?

Answer 30

Ionic compounds can conduct electricity but only when they are molten or have been dissolved in water. This is because the ions are free to move in a liquid state. Covalent compounds do not conduct electricity because they don’t have any ions - charged particles. Their molecules are uncharged. However some covalent compounds react with water to form ions and these can conduct electricity.

Question 31

What are the differences between ionic and covalent compounds related to volatility?

Answer 31

Ionic compounds are non - volatile as there are strong electrostatic forces of attraction between the oppositely charged ions, so a large amount for energy is needed to break the strong bonding and change the state of matter (into a gas). Covalent compounds are volatile in nature as there are weak intermolecular forces of attraction between the molecules so not a lot of energy is required outbreak them and it can easily change states of matter.

Question 32

What does volatility mean?

Answer 32

Volatility refers to how easily a substance will vaporise thus change states of matter into a gas.

Question 33

What are the differences in melting and boiling points between ionic and covalent compounds? (in terms of attractive forces).

Answer 33

Ionic compounds have a giant ionic lattice as structure. There are strong electrostatic forces of attraction between oppositely charged ions that require a lot of energy to break causing them to have high melting and boiling points. Covalent compounds have a giant covalent structure/lattice as structure. However, there are weak intermolecular forces of attraction between the molecules so not a lot of energy is required to break them causing it to have low melting and boiling points.