Bonding and Structure

Question 1

What structure does a metallic bond form?

Answer 1

A giant metallic lattice

Question 2

What structure does an ionic bond form?

Answer 2

Giant ionic lattice

Question 3

What structure does a covalent bond form?

Answer 3

• Giant molecular - covalent bonding throughout the structure
• Simple molecular - weak intermolecular forces.

Question 4

Give the definition of an ionic bond

Answer 4

Strong electrostatic force of attraction between the oppositely charged ions

Question 5

How does a giant ionic lattice form?

Answer 5

• Metal transfers its electrons to the non-metal to increase stability of each atom
• However, the positive and negative charges do not just point in one direction, they span out to create a giant 3D structure
• There is a constant state of repulsion between same charged ions and attraction between oppositely charged ions
• All of the forces find a balance as ions form a giant ionic lattice

Question 6

How do you draw a dot and cross diagram for an ionic bond?

Answer 6

1. Determine charge of metal
2. Draw metal without its outer electrons
3. Determine charge of non-metal
4. Work out formula of ionic compound
5. Draw the electrons on outer shell as dots on the non metal
6. Draw crosses on non metal as electrons gained from the metal
7. Add charges

Question 7

Give three physical properties of ionic compounds

Answer 7

1. High melting points and boiling points, giant ionic lattice structure, many strong electrostatic forces of attraction between ions, requires a lot of energy to overcome - greater ionic charge, stronger ionic bond - smaller atomic radius, stronger ionic bond.
2. Electrical conductivity - will not conduct electricity in the solid state, ions are in a fixed position. Will conduct electricity in the molten (or aqueous) state, ions are free to move
3. Dissolve in water, ions make attractions to the different atoms in water and are pulled apart

Question 8

Give the definition of a covalent bond

Answer 8

• A shared pair of electrons between atoms

Question 9

How does a double covalent bond form?

Answer 9

• When two pairs of electrons are shared between atoms.

Question 10

Can the central atom be stable with fewer than 8 electrons in a covalent molecule in some cases? Give two examples.

Answer 10

Yes
BF3 and AlCl3

Question 11

Can the central atom a covalent molecule fit more than 8 electrons in its outer shell if its in period 3 or higher?

Answer 11

Yes

Question 12

What are lone pairs?

Answer 12

If an atom does not use all of its outer electrons, these spare electrons are called lone pairs

Question 13

Explain coordinate/dative covalent bonding

Answer 13

• Occurs when one atom provides both the electrons needed to form a covalent bond
• Atom donating must have a lone pair, atom receiving must have a vacant orbital
• The bond is represented as an arrow pointing to the direction in which the electrons are being given