C2.2- Bonding

Question 1

What’s a physical property?

Answer 1

A characteristic that can be observed or measured

Question 2

Physical properties of metal elements:

Answer 2

• shiny
• high melting/boiling point
• solid at room temp
• malleable (they bend without breaking)
• ductile (they can be pulled into wires)
• good conductors

Question 3

Physical properties of non-metal elements:

Answer 3

• dull
• low melting/boiling point
• at room temp half are solid, half are gas
• brittle (they shatter when hammered)
• non-ductile (they snap when pulled)
• poor conductors (they’re insulators)

Question 4

What’s a chemical property?

Answer 4

• a characteristic of a substance that can only be determined by studying its chemical reactions

Question 5

How are elements arranged in the periodic table?

Answer 5

• a period is a horizontal row

- a group is a vertical column

Question 6

What are ions?

Answer 6

• an ion is an electrically charged particle formed when an atom, or group of atoms, loses or gains electrons
• metal atoms lose electrons to form positive ions
• non metal atoms electrons to form negative ions

Question 7

How do ionic compounds form?

Answer 7

• when a metal reacts with a non metal electrons are transferred from the metal atoms to the non metal atoms
• both achieve a more stable electronic structure

Question 8

What is the structure and bonding in ionic compounds?

Answer 8

• ionic compounds in their solid state contain positive and negative ions arranged in a regular way
• this arrangement is called a giant ionic lattice
• the ions are held in place by ionic bonds, which act in all directions

Question 9

What’s an ionic bond?

Answer 9

• ionic bonds are strong electrostatic forces of attraction between oppositely charged ions

Question 10

What are covalent bonds?

Answer 10

• a shared pair of electrons
• form between two non metal atoms when the atoms get close enough to share electrons in their outer shells
• by sharing they complete their outer shells

Question 11

What are simple molecules?

Answer 11

• a molecule is a particle in which non-metal atoms are joined to each other by covalent bonds
• a simple molecule is a molecule that only contains a few atoms

Question 12

What is the structure and bonding in simple molecules like?

Answer 12

• involve electrostatic forces of attraction
• the forces are between the nucleus of each bonded atom and the shared electrons
• the covalent bonds between an atom in a simple molecule are strong
• the intermolecular forces between the molecules are weak

Question 13

What are giant covalent structures?

Answer 13

• consists of very many non metal atoms joined by covalent bonds and arranged in a repeating regular pattern called a giant lattice
• also called giant covalent structures

Question 14

What are polymers?

Answer 14

• whether they’re artificial or natural they’re made from many smaller molecules called monomers
• these monomers are able to join end to end in chemical reactions, producing longer polymer molecules

Question 15

What are monomers?

Answer 15

• simple molecules
• consist of a few non metal atoms joined together by covalent bonds
• usually modelled by ball and stick diagrams, space filling models and dot and cross diagrams

Question 16

How are polymer molecules modelled?

Answer 16

• each polymer molecule is drawn as a wavy line
• sometimes have straight lines between them to represent covalent bonds between individual polymers
• they’re are weak intermolecular forces between polymer molecules

Question 17

What is the structure of metals like?

Answer 17

• all metals (apart from mercury) are in solid state at room temp
• their atoms are packed together in a regular way, forming a giant metallic lattice

Question 18

What are metallic bonds like?

Answer 18

• electrons leave the outer shells of the metal atoms, forming a sea of electrons around a positively charged metal ions
• these electrons are free to move through the structure of the metal so they’re called delocalised electrons
• metallic bonds are the strong electrostatic forces of attraction between the delocalised electrons and the closely packed, positively charged metal ions

Question 19

What did Mendeleev do?

Answer 19

• arranged the element in order of increasing atomic mass
• grouped together the ones with similar chemical properties
• swapped the positions of iodine and tellurium because he felt that this matched their chemical properties better
• left spaces for elements he thought would exist but weren’t yet discovered
• did not know of the atomic number since protons weren’t yet discovered