Periodic Table Flashcards
(26 cards)
How did they organise the elements before they organised them to what?
Atomic mass
Now: physical state and chemical properties and relative atomic mass
Why was newlands work criticised?
- groups contained elects that didn’t have similar properties
- mixed up metals and no metals
- didn’t leave gaps for more elects to be discovered
What did Mendeleev do differently to Newland?
Put elements in order of mass but left big gaps
What are the elements ordered in now?
Electronic structures - their energy levels
Why do metals that go further down group 1 become reactive?
Nucleus further away from electrons - less attraction and more shielding, electron is in a higher energy level is more easily lost
What does a increased distance and shielding mean?
Higher energy level is likely to gain electron because there’s less attraction from nucleus - why group 7 elements when you go down the group
As you go doen group 1 the elements become…?
More reactive-outer electron more easily lost because its further away from nucleus
Have lower melting and boiling points
What elements react vigorously in water? What do they produce?
Lithium sodium potassium
Hydrogen
What are group 7 elements called?
Halogens
As you go down group 7 the elements become…?
Less reactive - harder to gain outer electron
Higher melting and boiling point
What do the halogens form when they ionically bond?
1- ions called halides
A more reactive halogen can…? from a…?
Displace a less reactive halogen from an aqueous solution of its salt
What are the transition metals?
Metals between group 2 and 3
What properties do transition metals have?
- good conductors
- dense, strong, shiny
- less reactive
- higher boiling points and stronger than group 1
What do transition metals make?
Good catalysts eg. Iron in the harder process
what is meant by activation energy?
the energy needed for the reaction to take place
why is it good to use a calorimeter when measuring energy?
because it is metal no glass therefore it conducts the heat from the fuel better
why should you stir the water heating by the fuel when measuring the energy?
so the heat is evenly distributed around the container
why do we use a polystyrene cup when measuring energy?
because it’s a good insulator so less heat escapes making it more accurate
how could you improve the experiment with the polystyrene cup?
put a lid on it to reduce heat loss to air
stir the reaction to make sure temperature changes are evenly spread through the solution
speed = ?
distance / time
in distance time graph the gradient equals?
speed
flat sections in a distance time graph mean?
it’s stationary
downhill sections in a distance time graph means what?
it’s going back towards the starting point
