Structure and Bonding Flashcards
Diagram for solid, liquid and gas.
Have you drawn arrows in liquid and gas?
What is the relationship between each particle, are they stuck tg or not?
Check
SOLIDS
- Compression ability
- Shape
- Can particles move?
- Hard to compress because there are almost no spaces between particles
- They have a fixed shape because particles are not free to move (can’t flow)
- Particles can ONLY vibrate in a solid
LIQUIDS
- compression ability
- shape
- can particles move?
- Hard to compress because almost no spaces between the particles
- They don’t have a fixed shape and particles are free to move (can flow)
- Liquids take the shape of their container
GASES
- compression ability
- shape
- can particles move?
- Easily compressed because particles have a lot of spaces between them
- They don’t have a fixed shape, gas particles are free to move - the move randomly and quickly
- So they fill the shape of their container
How can the state of a substance be changed?
By putting in or taking out energy from the substance
Solid to liquid
= MELTING
- Thermal energy is input into the solid substance and solid’s particles have more KE
- Particles can vibrate and intermolecular forces of attraction are broken.
- This occurs at the melting point.
Liquid to gas
BOILING
- Thermal energy is input into the liquid substance so its particles have more KE
- Particles vibrate and IMF are broken
- This occurs at the boiling point
gas to liquid
= CONDENSATION
- Thermal energy is removed from the gas so its particles have less KE
- Particles move less and IMF are reformed
- Condensation occurs at the same temperature as boiling of the liquid. (cool it down to its Bp temp)
liquid to solid
FREEZING
- Thermal energy is taken out from liquid particles so they have less KE so less movement
- IMF are reformed
- Freezing takes place when we cool a liquid back down to its melting point temp
The stronger the IMF forces of attraction, the _____ energy needed to break the bonds, this means it has a higher what?
More energy
Higher melting point/boiling point
Limitations of the simple particle model of matter x2
- Assumes that all particles are solid inelastic spheres, this isn’t true particles have lots of shapes and aren’t always solid
- In SPM, assumes there are no IMF of attraction, not true, IMFOA are what keep particles tg in solid + liquid
Why do elements react?
Elements react so they achieve a full outer energy level to achieve the stable electronic structure of a noble gas (full outer shell)
When a metal and a non-metal react, what type of bonding takes place?
Ionic bonding
What happens during the ionic bonding between group 1 metals and group 7 non-metals?
- Group 1 metal lose 1 electron and become a 1+ ion (1)
- That electron is gained by the group 7 non-metal atom to become a 1- ion (1)
- Both atoms now have a full outer shell (1)
- This occurs during ionic bonding to form a metal halide compound(1)
How do we represent ionic bonding?
Dot and cross diagram, only showing outermost energy level.
- OR energy level diagrams.
Describe what happens during ionic bonding between a group 2 and group 6 atoms
- Group 2 metal lose 2 electrons and become a 2+ ion (1)
- The 2 electrons are gained by the group 6 non-metal atom to become a 2- ion (1)
- Both atoms now have a full outer shell (1)
- This occurs during ionic bonding
Describe what happens during ionic bonding between a group 7 and group 2 atom
- Group 2 metal lose 2 electrons and become a 2+ ion (1)
- Those electrons are gained by 2 group 7 non-metal atoms (1 to each) to each become a 1- ion (1)
- Both atoms now have a full outer shell (1)
- This occurs during ionic bonding to form a metal halide compound(1)
*remember to always balance equations and write electronic structure in numbers in brackets + ALWAYS CHECK
True or false many ionic compounds are crystals?
True.
Ionic compounds are formed from what type of bonding?
Ionic bonding
Describe the structure of ionic compounds.
- Form giant ionic lattices (giant ionic structures)
- 3 dimensional
- Every positive ion is surrounded be a negative ion and vice versa - so strong electrostatic forces of attraction.
What is a lattice?
The regular three-dimensional arrangement of ions in an ionic compound, held together by strong electrostatic forces of attraction.
What type of bonds hold ionic compounds together?
Strong electrostatic forces of attraction -> these act in all directions and hold the positive and negative ions in place.
so why do ionic compounds have high melting and boiling points?
- They have strong electrostatic forces of attraction between ions.
- Cannot conduct electricity because ions are locked in place by strong electrostatic forces of attraction, so are not free to move and carry electrical charge.
^^can only conduct electricity when molten or dissolved in water - as ions can now move and carry electrical charge.
Electrostatic forces of ATTRACTION is also known as?
Ionic bonds
(+ and -)
On spec, look at the diagrams that ionic bonds can be displayed.
Check, and draw
What is covalent bonding?
When a non-metal and non-metal bond tg. (2 non metals).
Example of covalent molecule
H2 (hydrogen)
^diatomic, only 1 electron on outermost shell of ONE hydrogen atoms, so covalently bonds w another and their outermost shell overlap to form covalent molecule H2 - both H atoms have are stable and achieve structure of noble gas.
Same thing occurs w group 7, overlap outermost energy level 2 get 1 extra electron in each.
True or false, covalent bonds are strong?
True
3 diagrams to represent bonding:
- Stick diagram (eg F - F or C = C)
- Dot and cross diagram
- Energy level diagram (circles overlap)
True or false, only the outer energy levels are involved in chemical bonding?
True, that why we only draw them in bonding diagrams
Practice
Draw covalent bond for hydrogen and chlorine in stick diagram, dot-cross diagram and energy level diagram
check