C2,C3,C4 Flashcards
Sodium chloride is an ionic compound.
Describe the structure of a crystal of sodium chloride
Ionic compounds such as sodium chloride are arranged in a giant lattice structure, which is a regular repeating pattern of positive and negative ions. There are strong electrostatic forces of attraction that hold the oppositely charged ions together in the giant lattice.
Why does sodium chloride have a high melting point
Sodium chloride has a high melting point and boiling point because of the strong electrostatic attraction between its positive and negative ions. This requires more heat energy to overcome the force of attraction.
Name the force that holds ions together in an ionic bond
Electrostatic force
From a dot and cross diagram, how can you tell that the particles in a compound are held together by an ionic bond
The electrons from one atom are shown as dots, and the electrons from the other atom are shown as crosses
Choose the correct words
In an ionic compound, the particles are held together by weak/strong forces of attraction.
These forces act in all directions/in one particular direction which results in the particles bonding together to form giant lattices/small molecules.
Strong forces of attraction.
In all directions.
Giant lattices.
Which of the following is not typical for an ionic compound
High melting point
High boiling point
Conduct electricity in the solid state
Conducts electricity in the liquid state
Conduct electricity in the solid state
How does the structure of the ionic compound pottasium bromide cause it to have a high boiling point
Ionic compounds have high melting and boiling points because they have a giant structure with strong electrostatic forces between oppositely charged ions that require a lot of energy to break
How does the structure of the ionic compound pottasium bromide cause it to have a low electrical conductivity of solids
Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move
How does the structure of the ionic compound pottasium bromide cause it to have a high electrical conductivity as a liquid
Ionic compounds can conduct electricity when melted or dissolved in water. During these states, the charged particles called ions are able to move freely. In contrast, the ions are stationary when the ionic compound is in a solid crystalline state
Decribe how two atoms come together to form a single covalent bond
A covalent bond is formed when a pair of electrons is shared between non metal elements
Describe how the hydrogen atoms in a methane molecule are bonded to the carbon atom
For example, in methane (CH 4 ), carbon forms covalent bonds with four hydrogen atoms. Each bond corresponds to a pair of shared electrons (one from carbon and one from hydrogen), giving carbon the eight electrons it needs for a full outer shell.
compare the strength of the bonds of covalent, metallic and ionic.
Which is stronger?
The covalent bond is usually weaker than the metallic and the ionic bonds but much stronger than the intermolecular forces
When a simple molecular substance melts, is it the bonds between atoms or the forces between molecules that are broken?
The forces between the molecules are broken
predict with reasons whether iodine can conduct electricity in any state
There are no delocalized electrons in iodine, and no ions, so there are no charge carriers and iodine cannot conduct electricity.
Why does methane have a lower boiling point to that of butane
Butane is a larger molecule than methane meaning that the intermolecular forces between its molecules are stronger. In order for a compound to boil these intermolecular forces need to be overcome.
