Lesson 2: Ionic bonding+ Properties Flashcards
What is an ionic bond?
- A strong bond between metal and non- metal.
What holds positive and negative ions together to form ionic compound?
- Electrostatic force holds negative and positive ions.
What structure do ionic compounds have?
- Giant ionic lattices. Electrostatic force of attraction acts in all directions between oppositely- charged ions.
What is a giant ionic lattice?
- A giant ionic lattice is a large, repeating structure made of oppositely charged ions.
Give 1 P and N of ball and stick models.
P: show repeating pattern in all directions (not just surface)
N: spaces between ions suggests gas.
Give 1 P and N of 3D space- filled models.
A: Shows how close ions are
D: Only illustrates outermost layer of compound.
Give 1 P and N of 2D space- filled diagrams.
P: shows how close the ions are.
N: No idea of 3D structure.
True or False
A salt crystal is an element that makes up a compound.
- False! Salt crystal is a compound that contains millions of ions.
Crystals have a square shape from lattice structure
What are crystals?
- This is the structure ionic compounds form.
IT IS A GIANT IONIC LATTICE
What type of crystal structure do ionic compounds form?
- Giant ionic lattices
What does molten mean?
- Means melted/ liquid
What are the 3 properties of ionic compounds?
- High melting and boiling points
- Soluble
- Conduct electricity when dissolved / molten
Why do ionic compounds have high melting and boiling points?
- Strong electrostatic force of attraction between positive and negative ion.
- Requires a lot of energy to break.
Why doesn’t distilled water conduct electricity?
- No dissolved ions that can carry the charge/current in circuit.
Why can’t an ionic solid conduct electricity?
- Ions can’t move due to strong forces of attraction in all direction.
- Ions can’t carry charge.
Why do ionic compounds conduct when in solution/ molten?
- Ions are free to move/ and carry the charge (to allow current to flow)
True or False…
In an ionic solution, the electrons move to allow charge to flow.
False.
- It is the ions that are moving.
Why are ionic compounds hard?
1.) Have strong electrostatic forces that act in all directions.
2.) This forms lattice shape.
3.) Theses forces are hard to break.
What is the P + N of the dot- cross diagram?
P: Shows where electrons come from.
N: Doesn’t give idea of shape of lattice.
What is the empirical formula?
- Just the normal formula for a compound.
BUT - By diagram, count the ions for each element and put in simplest ratio.
Describe the structure of NaCl
- Giant ionic lattice made of Na⁺ and Cl⁻.
- Opposites held by electrostatic force of attraction
- This force acts in all directions and forms giant lattice of alternating ions.
Why do solid ionic compounds not conduct electricity?
- Ions can’t move due to electrostatic forces of attraction in all direction
Q.)
Describe, in terms of electron arrangement, the type of bonding in:
(i) The compound sodium chloride
- Sodium outer shell = 1
- Chlorine outer shell = 7
- Sodium loses 1 electron
- Chlorine gains 1 electron
- Sodium = Na+, chlorine = Cl-
- Ions held by ionic bond
Why do elements react?
- Elements react to achieve a full outer energy level.
- Have electronic structure of noble gas.
Describe what happens when sodium reacts with chlorine (4)
- One electron
- Passes from sodium atom
- To chlorine atom
- Both atoms achieve a full outer- energy level.
