Bonding

Question 1

How ionic bonding occurs?

Answer 1

Ionic bonding occurs between metals and non-metals

Question 2

Structure of an ionic bonding

Answer 2

-Giant lattice structure

Lattice is a regular, three-dimensional arrangement of ions.

Question 3

Properties of ionic bonding

Answer 3

• High melting point

- Giant lattice structure

Question 4

How strong melting point are caused

Answer 4

Strong electrostatic attractions give ionic compounds high melting point.

Question 5

Positive ions

Formation & charges

Answer 5

• Generally formed by Metal atoms losing electrons.
• Positive charge equal to the group number if formed from a group 1, 2 or 3 element.
• Different charges if formed from transition metal
• Knows as cations

Question 6

Negative ions

Formation & charges

Answer 6

• Generally formed by non-metal atoms losing electrons
• Negative charge equal to 8 minus the group number of the element.
• Sometimes exist as polyatomic ions such as OH-
• Known as Anions

Question 7

Strength of ionic bonding

Answer 7

To compare the relative strength of ionic bonds, the ionic charge and ionic radius have to be considered, sometimes called the charge/size ratio.
Example-
The ionic bonding in Mgf2 is much stronger than the bonding in NaF- this is because the magnesium ion is smaller than the sodium ion and also greater in charge. These factors increase electrostatic attraction between the ions.

Question 8

what are covalent bonds ?

Answer 8

A covalent bond is an electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 9

How covalent bonds forms?

Answer 9

A covalent bond forms when atoms share a pair of electrons. Generally, each atom in the bond contributes one electron to the pair.

Question 10

What is a dative covalent bond?

Answer 10

A covalent bond consisting of an electron pair derived from one of the atoms.

Question 11

How are covalent bonds shown?

Answer 11

In dot and cross diagrams

Question 12

How are ionic bonds shown?

Answer 12

In an electron configuration diagrams

Question 13

Strength of covalent bonds

Answer 13

Bond length and bond strength in covalent bonds are inversely related. This means that the shorter the covalent bond length, the greater the covalent bond strength.

Question 14

What is a metallic bonds?

Answer 14

Is a bond between two metal elements

Question 15

Structure of metallic bonds

Answer 15

A giant lattice of positive ions with delocalised electrons.

Question 16

What are delocalised electrons?

Answer 16

The electrons from the outer shell of the metal atoms, but are not fixed to a particular atom so they can move freely throughout the structure.

Question 17

Properties of metals

Answer 17

-Electrical and thermal conductivity
> Due to the delocalised electrons, which are free to move
-High melting and boiling point
>Due to strong electrostatic attractions between positive ions and electrons
-Malleability
>Layers of positive ions slide over each other and the delocalised electrons move with the layers
-Ductility
> Positive ions roll over each other and the delocalised electrons move with the positive ions.

Question 18

Trends in melting points- Group 1 metals

Answer 18

Melting point decreases as the atoms get larger.

larger metals have more electrons and more electron shells, means they have more shielding between the nucleus and delocalised electrons. So the electrostatic forces are weakened, this produces weaker metallic bond, so less energy is required to break the bonds.

Question 19

Trends in melting points- Group 2 metals

Answer 19

Has a higher melting point than the group 1 metals in the same period.

Because the group 2 metal has two delocalised electrons per positive ion, rather than one.