Chemistry unit2 Flashcards
What is an ionic bond
A bond between a metal and a non metal made via the electrostatic attraction between the oppositely charged atoms. The atoms gain or lose electrons to get a full outer shell
What is a covalent bond
A bond between two non-metals where they share electrons with each other to get full outer shells
What is metallic bonding
The electrostatic attraction between the positively charged metal ions and the negatively charged delocalised electrons
How are ionic compounds held together
In a giant lattice structure, the electrostatic forces act in all directions between the ions
How do the two types of covalent molecules differ in bonding
-simple molecular covalent bonding was intermolecular forces that hold them together in smaller structures
-Giant covalent structures have a giant lattice structure with strong intermolecular forces to hold them together. like diamonds or silicon dioxide
How does metallic bonding work
each metal in the compound will have at least one delocalised electron and these delocalised electrons are spread evenly throughout the metal so that the attraction between the metal ions and the electrons keeps the structure together
3 states of matter
Solid, liquid, gas
What determines the state of an object
The strength of the bonds in its structure as the weaker the bonds in the structure are, the less energy needed to overcome them and so a lower temperature is needed.
What could be a limitation of the simple model of showing states
-Not 3D
-All forces shown are solid spheres but that isn’t the case
-Doesn’t show us the energy in each state
Properties of ionic compounds
-High boiling and melting points so usually solid (or aqueous)
-When aqueous, they conduct electricity as the lattice structure breaks down and the ions are free to move through the structure
-Hard and brittle
-Made up of ions
Properties of simple molecular covalent bonding
-They have weak intermolecular forces holding them together so the bonds don’t actually break
-no electrical charge so no conducting of electricity
-Low boiling and melting points
-The larger the molecule, the higher the melting point
Properties of Metallic Bonding
-Weak forces between each layer of the ions so the metal is malleable
-High melting and boiling points
What is an alloy and why do we have them
A substance made up of two or more metals.
The different sizes of the ions in the metals means that they cant slide as easily so they are usually tougher than a pure metal
Why are metals good conductors
The delocalised electrons can carry an electrical charge or thermal energy through the metal structure
What are the properties of a polymer
-Very large molecules
-Have strong covalent bonds between the atoms
-Strong intermolecular forces help keep the polymer solid at room temperature
