C2:The periodic table Flashcards
Why did Mendeleev leave gaps?
Prediction of future elements.
Who invented the modern periodic table?
Mendeleev
What is the period table organised by?
Atomic mass
How can you determine the amount of electrons in the outer shell?
Group number
Common properties of metals:
-Conduct electricity
-Higher B+M points
-Ductile
-Malleable
Common properties of non-metals:
-Brittle
-Low B+M points
-Electrical insulators
What is different about the noble gases?
They are extremely unreactive.
Why are group 0 elements unreactive?
They already have a full outer shell.
Properties of alkali metals:
-Very reactive
-Low density (float on water)
-Soft and shiny (until react with oxygen and go dull)
Why are alkali metals stored in oil?
So they don’t react with the oxygen in the air.
Equation for alkali metals and water:
alkali metal + water =
metal hydroxide + hydrogen
What are the melting and boiling points like for alkali metals?
Low, they are reactive. Get lower down the group.
As you go down the alkali metals, what happens to the reactivity?
Goes up
What do we expect to happen when alkali metal reacts with water?
Fizzing (hydrogen gas), metal floats and moves around.
Potassium’s reaction is so vigorous that the hydrogen produces a lilac flame.
What colour does universal indicator turn the water after alkali metal + water?
Purple (alkali)
Reaction of alkali metals with halogens:
metal halide (e.g sodium chloride)
What does a metal halide produce when formed?
Dissolve in water to form colourless solutins.
Properties of halogens:
-low melting and boiling points (goes up going down the group)
-poor conductors of heat and electricity
-all exist in pairs of atoms (diatomic molevules)
What do halogens need to do to become an ion?
Gain 1 electron on their outer shell.
What happens to the reactivity of halogens as you go down the group?
It goes down.
What is a displacement reaction?
A more reactive halogen will displace a less reactive halogen from solutions of its salts.
As you go down a group in the periodic table, the number of shells occupied by electrons ______.
Increases
Larger atoms lose electrons _____ going down a group.
easier
Larger atoms gain electrons ____ going down a group.
Less easier
What is the attraction between electron and nucleus callled?
Electrostatic attraction.
What effect can shells on inner shells have on the outer shell electrons?
Shielding effect, less electrostatic attraction.
What are groups 2 and 3 also known as?
Transition elements.
Properties of transition metals:
-good conductors of electricity and heat
-hard and strong
-high densities
-high melting points (other than mercury)
Transition metals typically have very _____ reactions.
slow (e.g rusting)
What are transition metals useful as?
Structural materials.
Transition metals often form very ____ compounds.
Colourful (like copper sulfate being blue)
