2.1: Chemical bonds and types of bonding

Question 1

What are three types of bonding?

Answer 1

There are 3 types of strong chemical bonds: ionic, covalent and metallic.

Question 2

What is ionic bonding?

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Answer 2

● Metal + Non-metal: electrons in the outer shell of the metal atom are transferred
○ Metal atoms lose electrons to become
positively charged ions
○ Non-metal atoms gain electrons to become
negatively charged ions
● Electron transfer during the formation of an ionic compound can be represented by a dot and cross diagram

Question 3

What are ionic compounds?

Answer 3

● A giant structure of ions.
● Held together by strong electrostatic forces of attraction between oppositely charged ions
● Since the structure is in 3D, the forces act in every
direction.

An example is sodium chloride (salt)

Question 4

What is covalent bonding?

Answer 4

● Covalent bonding is between two non-metals

Question 5

What are the differences between different-sized covalent structures?
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Answer 5

● Small molecules, such as: HCl, H2, O2, Cl2, NH3, CH4 have strong covalent bonds within their molecules.
● Giant covalent structures (macromolecules) consist of many atoms covalently bonded in a lattice structure. For example: diamond, silicon dioxide.
● We use dot and cross diagrams to show these

Question 6

How are metallically bonded compounds structured, and how is their electronic structure different?

Answer 6

● The bonding in a metal consists of positive ions (atoms that have lost electron(s)) and delocalised electrons arranged in a regular pattern.
● The delocalised electron system consists of the electrons ‘lost’ from the atoms to form positive ions.
● Delocalised electrons are free to move through the structure.
● The delocalised electrons are shared through the structure so metallic bonds are strong.