C3 Structure and Bonding Flashcards
What are the 3 states of matter?
Solid, Liquid and Gas
How are solid particles arranged?
- Tightly packed
- Arranged in rows
- Vibrate in fixed positions
- Fixed shape and volume
- Low kinetic energy
- Cannot be compressed
How are liquid particles arranged?
- Close together
- Irregular pattern
- Can slide past each other
- Shape can change
- Fixed volume
- Medium kinetic energy
- Cannot be compressed
How are gas particles arranged?
- Widely spaced
- Arranged randomly
- Move freely in all directions
- Change shape and volume
- Most kinetic energy
- Can be compressed
What are all the change in states?
Melting - Solid to liquid
Freezing - Liquid to solid
Evaporate - Liquid to gas
Condensing - Gas to liquid
Sublimation - Solid to gas
Deposition - Gas to solid
What happens to bonds during a change of state?
Bonds are either being broken or being made. Thermal energy added is used to break existing bonds between the molecules within the substance while thermal energy lost is replaced as new bonds form
Breaking bonds - Endothermic
Making bonds - Exothermic
Why do atoms form bonds?
Each shell has a maximum number f electrons that it can hold. Electrons fill the shells nearest the nucleus first
What are the types of bonds?
Ionic - between metal and non-metal
Covalent - between non-metals
Metallic - between metals
What are ions?
A charged particle formed when an atom gains or loses electrons.
Why can ions not be neutral?
Atoms are neutral because the number of protons = electrons and neutrons have a neutral charge. When the atom gains or loses an electron to become an ion, the number of protons and electrons won’t be balanced, therefore they will not cancel each other out.
What is a half equation?
Show each separate process in terms of electron movement. E.g. (Al3+) + (3e-) → Al. Aluminium ion gains three electrons to become an aluminium atom
What is ionic bonding?
- Occurs when oppositely charged ions attract and bond together
- Happens between metals and non-metals
- Held in a giant lattice by strong electrostatic forces
What is the empirical formula?
Simplest whole number ratio of atoms present in a compound. E.g. Glucose formula is C6H12O6 -> 6 carbon, 12 hydrogen, and 6 oxygen atom. The empirical formula of glucose is CH2O (everything divided by 6)
What is the structure of ionic compounds?
- Strong electrostatic forces between positively and negatively charged ions - hard
- This forms a lattice -> regular, ordered structure of repeating units
- All ionic compounds form lattices and crystals when solid
Why are ionic compounds brittle?
- Layer of ions is shifted when the lattice is hit so that ions with the same charges are lined up
- These repel each other and so split the ionic lattice causing it to shatter
Why do ionic compounds have high melting and boiling points?
Ionic compounds form giant lattices (repeated structure)
- There are strong electrostatic forces between oppositely charged ions
- Lots of energy is needed to overcome these forces
Why do some ionic compounds form solutions with water?
The water molecules will break up the lattice into ions (Giant ionic compounds will dissolve)
Why can ionic compounds conduct electricity when in solution or molten, but not when they are solid?
- Solids do not have free ions
- Molten can conduct electricity -> ions are free to move around and conduct
What is a covalent bond?
- Two non-metal atoms cannot form a bond by transferring electrons from one to another.
- Instead, they share electrons.
- Shared electrons join the atoms together.