Topic 1 Flashcards
Who created the periodic table?
Mandeleev (Dmitri)
How is the periodic table arranged?
columns, rows, types
vertical columns : called groups - linked to the number of electrons in the outer shell
Horizontal rows : called periods - linked to the number of electron shells.
Metals and non metals seperated, Metalloids, Nobel gases.
What makes an atom stable? Are they reactive, why?
must have a full outer shell.
Unreactive (will not gain or lose any electrons, which needs to happen for an element to react)
What happens when an atom gains or loses an electron?
Turn into ions.
Add or subtract an electron =
ion
add or subtract a proton =
new element
add another atom =
2 answers
Molecule or Compound.
add or subtract a neutron =
Isotope
About an Isotope
change to particles, reactions, weight
- same number of protons, different neutrons
- same atomic number, different mass number
- react in the same way (electrons cause reactions)
- Heavier
How to name an ion
Positive (lose e-) : same name + ‘ion’ afterwards
Negatice (gain e-) : same name add ‘ide’ suffix.
What is an element?
Pure substances made up of any one type of atom.
What is a compound?
pure substances which are formed when 2 or more elements chemically combine.
What is a mixture?
Not pure substances. Contain more than one substance (either element or compound) that are not bonded together.
What is an alloy? Purpose
A mixture of metals. The atoms are not chemically bonded.
Have different properties, can be harder stronger etc.
Group 1 & 2 trends
- going down reactivity increases
- going down melting points and boiling points decrease
Group 7 trends
- going down reactivity decreases
- sunstance state changes from Gas to solid
What is Chromatography used for?
technique used to seperate mixtures of a soluble solid so they can be identified
What does Rf value mean and tell us?
retention factor - used to identify components.
Larger Rf value means more soluble in solvent
Smaller Rf value means less soluble
How to calculate Rf value
distance travelled by component from baseline / distance travelled by the solvent.
How do you make a colorless substance visible?
made visible by using a locating agent
e.g. ninhydrin
Traits of solid particles
packed, move, attraction, arrangement, compressed, diffused, kinetic ene
- Packed closely together
- cant move freely but vibrate
- Strong forces of attraction holding them together
- regular arrangement
- cant be compressed
- cant diffuse
- lowest kinetic energy
Traints of Liquid particles
packed, move, attraction, arrangement, compressed, diffuse.
- still touching
- can move freely/ slide past eachother
- less strong forces of attraction
- disorderd irregualr arrangement, can take the shape of any container its in
- cant be compressed
- diffuse slowly
Traits of Gas particles
packed, move, attraction, arrangement, compressed, diffused, kinetic ene
- spread out and move freely
- no forces of attraction holding them together
- irregualr arrangement, no fixed shape. will completely fill a container
- can be compressed
- diffuse rapidly
- highest kinetic energy
How does state change?
using energy. More thermal energy particles have the more kinetic energy they have. Increased energy causes forces of attraction (bonds to break) allowing state change to occur.
What makes a substance pure?
compisition, properties
- definite composition - is a sample is taken from any part of the substancr the properties will remain the same
- defined properties. boling, melting point always the same.
Soluble meaning
solid able to dissolve in a liquid
Solute meaning
Solid that can dissolve in a liquid
Solvent meaning
liquid that can dissolve the solid
Solution meaning
mixture of a soluble solid and liquid
Insoluble meaning
solid is unable to dissolve in a liquid
How to seperate an insoluble solid and liquid
Filtration
e.g. sand and water
How to seperate a soluble solid and liquid
Evaporation, Crystallisation, Distillation
How to seperate immiscible liquids
seperating funnel
How to seperate miscible liquids
fractional distillation
Flat sections in heatung and cooling curves mean?
temperature reamins constant untill all particles have changed state
what is diffusion?
net movement of particles from an area of high concentration to a low concentration.
Do liquids or gases diffuse slower? why?
Liquids diffuse slower than gases vecause they have less kinetic energy.
Does weight affect diffusion?
yes, lighter particles diffuse faster than heavier particles
Does temperature affect diffusion?
Yes, higher tenperature creates more kinetic energy and a faster rate of diffusion.
