Periodic Table Flashcards
John Newlands
Arranged elements by increasing atomic weight
Noticed every eighth element had similar properties and coincided with the triads- law of Octaves
Dimitri Mendeleev
Refined Newlands ideas by using all known data for each element and arranging them into groups and periods
Periodic table established when a new element matched his prediction and filled a gap
Johann Döbereiner
Arranged elements in a pattern
Linked properties and found some made triads and that atomic weight of triad’s second element was average of the other two
Covalent bonding
Non metals combine by sharing electrons
What properties have covalent bonds
Low melting points, weak bonds and weak intermolecular forces
Do not conduct electricity
SHARED ELECTRONS
What kind of metals are in group one
Why do they have similar properties
Alkali metals
They all have one electron in outer shell
Why are alkali metals stored under oil
They react with air and vigorously with water
What colour does a lithium compound give when burned
Red
What colour does a sodium compound give when burned
Yellow
What colour does a potassium compound give when burned
Lilac
What is produced when alkali metals react with water
A hydrogen and a hydroxide
In group one are the metals more or less reactive the further down they are
More reactive
In group one what happens to boiling and melting points of the alkali metals, the further down they are
They both decrease
Why are the elements in group one more reactive the further down in the periodic table they are
Elements further down have outer shells further away from the nucleus making it easier for an atom to lose an electron from its shell
Is oxidation loss or gain of electrons
Loss
Is reduction loss or gain of electrons
Gain
What are non-metals in group 7 known as
How many electrons in outer shell
Halogens
Seven electrons in outer shell
Name first four halogens
Flourine
Chlorine
Bromine
Iodine
What are the states of flourine, cholrine, bromine and iodine at room temeprature
Flourine is a gas
Chlorine is green gas
Bromine is an orange liquid
Iodine is a grey solid
What are flourine, cholrine, bromine and iodine used for
Fluorine used in toothpaste
Chlorine sterilises water and makes pesticides and plastics
Iodine sterilises wounds
What do halogens react with to make metal halides
Halogens react with alkali metals to form metal halides
As we go down group 7 are the elements more or less reactive
Less reactive
Flourine is most reactive
In a water solution of its metal halide, what will a halogen displace
A halogen displaces a less reactive halogen, solution forms
Eg. If chlorine is passed through aqueous potassium bromine solution
Bromine is formed due to displacement
In group seven what happens to boiling points, melting points and density of the alkali metals, the further down they are
They increase
Why is flourine the most reactive of the halogens
It is easiest for it to gain the extra electron as the outer shell is closer to the influence of the nucleus
What metals are included in transition metals
They have typical qualities
Iron Copper Platinum Mercury Chromium Zinc
Compounds of transition metals are often coloured
What colour are copper compounds
Blue
Compounds of transition metals are often coloured
What colour are iron(II) compounds
Grey/green
Compounds of transition metals are often coloured
What colour are iron (III) compounds
Orange-brown
Transition metals and their compounds can be used as catalysts in chemical reactions
What are two examples of this
Iron is used in haber process
Nickel is used in manufacture of margarine
Thermal decomposition
Substance is broken down into simpler substances by heating
When transition metals are heated under thermal decomposition what occurs
Colour change
Decompose to form a metal oxide and carbon dioxide
When does limewater turn milky
When carbon dioxide us present
What is the reaction between transition metal ions and sodium hydroxide solution called
A precipitation reaction
In thermal decomposition of transition metal carbonates,
What are the products of copper carbonate (II)
Copper carbonate(II) = Copper(II) oxide + carbon dioxide
In thermal decomposition of transition metal carbonates,
What are the products of iron carbonate (II)
Iron carbonate(II) = Iron(II) oxide + carbon dioxide
What can metal compounds in solution form when sodium hudroxide solution is added to them
Precipitates (insoluble solids)
Iron is a transition metal what are it’s uses
Iron is used to make steel it is very strong
Steel used for cars
Copper is a transition metal what are it’s uses
Copper is a good conductor
Used for electrical wiring
Used to make brass
Give properties of metals
Lustrous eg. For jewellery
Hard with high density eg. For drill bits
High tensile strength to bear loads
High melting and boiling points
Good conductors of heat and electricity eg. saucepans and wiring
How are metal atoms held together and how are they arranged
As metal atoms pack together, what structure do they build
Metal atoms held together by metallic bond
Packed closely in regular arrangement
As metal atoms pack together they build a structure of crystals
Why do metals have high melting and boiling points
Metal held together by strong electrostatic attraction between metal ions and delocalised electrons
Lots of energy needed to overcome the strong metallic bonds
Why do metal atoms form a metallic bonds when they are packed together
Atoms packed so close the outer electron shells overlap and form metallic bonds
The overlap allows electron to be free (delocalised)
How can the structure of metallic bonds be described
Closely packed metal ions in a sea of delocalised electrons
In metal atoms, how are metals able to conduct electricity
The free movement of delocalised electrons allows metal to conduct electricity
Atoms close together and electrons can move from atom to atom
At low temperatures some metals can become superconductors
Describe a superconductor
A superconductor has very little or no resistance to the flow of electricity
Superconductors have low resistance, when is this useful
When you require:
A powerful electromagnet eg. Inside medical scanners
Very fast electronic circuits eg. Supercomputer
Power transmission that does not lose energy
Why are superconductors expensive to use
They operate at about -200’c which is costly and impractical
We are trying to find one that will work at room temperature
