C2-The Periodic Table Flashcards
How was John Dalton’s periodic table arranged?
In order of atomic weight
How was John Newland’s periodic table arranged?
In order of mass and in octaves as the properties of every eighth element seemed similar
Why was John Newland’s periodic table not accepted?
He assumed that all the elements had been found and did not take into account that chemists were still discovering new ones. So he filled in his octaves even though some of the elements were not similar.
How was Mendeleev’s periodic table arranged?
In order of atomic weight and in a regular occuring pattern of properties, with gaps for elements that had not yet been discovered
Why was Mendeleev’s periodic table approved years later?
He left gaps for elements which had not yet been discovered and used the table to predict what their properties should be
How are elements arranged in today’s periodic table?
In order of atomic (proton) number
Why do elements in the same group react in a similar way?
They all have the same number of electrons in their outermost shell
What is the name for group 1 elements?
Alkali metals
How does the reactivity of group 1 metals change going down the group?
It increases
Properties of the alkali metals
Very low densities, soft and shiny
How do the melting and boiling points of group 1 metals change going down the group?
They decrease
Reaction of alkali metals with water
Metal + water ——–> metal hydroxide + hydrogen
Why is there fizzing when you add lithium, sodium or potassium to water?
The metal reacts with the water to form hydrogen gas
Why is there a flame when potassium reacts with water?
It reacts so vigorously that the hydrogen produced ignites
Properties of the ionic compounds formed when alkali metals react with non-metals
They are white and dissolve easily in water. The solutions formed are colourless
What is another name for the group 7 elements?
The halogens
Properties of the halogens
-Low melting and boiling points
-Poor conductors of heat and electricity
Are the halogens diatomic?
Yes
How does the reactivity of the halogens change going down the group?
The elements get less reactive
What is the displacement reaction rule for the halogens?
A more reactive halogen will displace a less reactive halogen from solutions of its salts
What colour is fluorine?
Yellow gas
What colour is chlorine?
A green gas
What colour is bromine?
A red-brown volatile liquid
What colour is iodine?
A dark grey crystalline solid or a purple vapour
What does electrostatic attraction depend on?
-The distance between the outermost electrons and the nucleus
-The number of occupied inner shells (energy levels) of electrons, which provide a shielding effect
-The size of the positive charge on the nucleus (nuclear charge)
Physical properties of the transition elements
-Good thermal and electrical conductors
-Hard and strong
-High densities
-High melting points
Chemical properties of the transition elements
-Much less reactive that group 1 metals
-Often have to be heated before they react
What colour is Copper(II) Sulfate?
Blue
What colour is Nickel(II) Carbonate?
Pale green
What colour is Chromium(II) Oxide?
Dark green
What colour is Manganese(II) Chloride?
Pale pink
Why do transition elements usually include a roman number?
They can form more than one ion
What are transition elements used for?
As catalysts in the chemical industry
