C2 Flashcards
In the 1800s how were elements arranged?
They were arranged by atomic weight
What did Mendeleev do?
He put elements mainly in order of atomic weight but he did switch the order if an element had similar properties to the elements in that group. He also left gaps which indicated that some elements were yet to be discovered
What does the group number show in the periodic table?
It shows how many electrons are in the outer shell of the elements in each group
What are metals?
Metals are elements which can form positive ions when they react
Name some properties of metals
- They are strong and malleable
- They are great at conducting heat and electricity
- They have high melting and boiling points
What are some properties of group 1 metals? ( alkali metals )
- They have one electron in their outer shell so they are really reactive
- They are all soft and have a low density
Explain the trends for the alkali metals as you down group 1
- Increasing reactivity - the outer electron is more easily lost as the attraction between the nucleus and electron decreases, because the electron is further away from the nucleus the further down the group you go
- Lower melting and boiling points
- Higher relative atomic mass
What do alkali metals form when reacted with non-metals?
They form ionic compounds
The group 1 elements dont need much energy to lose their one outer electron to form a full outer shell so they easily form +1 ions
What happens when the group 1 elements react with water?
- They react vigorously to produce hydrogen gas and metal hydroxides
- The more reactive the metal is ( lower down in the group ) the more violent the reaction
- The amount of energy given out by the reaction increases while going down the group
What happens when the group 1 elements react with Chlorine?
The group 1 metals react vigorously when heated in chlorine gas to form white metal chloride salts
What happens when group 1 metals react with oxygen?
Group 1 metals can react with oxygen to form a metal oxide and different types of oxide will form depending on the group 1 metal:
- Lithium reacts to form lithium oxide
- Sodium reacts to form a mixture of sodium oxide and sodium peroxide
- Potassium reacts to form a mixture of potassium peroxide and potassium superoxide
Name some of the differences between group 1 metals and transition metals
- Group 1 metals are much more reactive than transition metals
- They are much less dense, strong and hard than transition metals and have much lower melting points
What are the group 7 elements called?
The halogens
What are the halogens?
The halogens are all Non-metals with coloured vapours
What is fluorine?
Fluorine is a very reactive, poisonous yellow gas
What is chlorine?
Chlorine is a fairly reactive, poisonous dense green gas
What is bromine?
Bromine is a dense, poisonous, red brown volatile liquid
What is iodine?
Iodine is a dark grey crystalline solid or a purple vapour
What are the trends in group 7?
As you go down group 7, the halogens:
Become less reactive
Have higher melting and boiling points
Have higher relative atomic masses
What can halogens form with other non-metals?
They can share electrons via covalent bonding in order to achieve a full outer shell and the compounds that form when halogens react with each other are called simple molecular structures.
What do halogens form with metals? ( ionic bonding )
Halogens form -1 ions called halides when they bind with metals
What is a displacment reaction?
A displacment reaction can occur between a more reactive halogen and the salt of a less reactive one. So it is when a more reactive halogen displaces the salt of a less reactive one
What are the group 0 elements called?
The noble gases
How much electrons do the noble gases have in their outer shell?
They have 8 electrons in their outer shell apart from helium which has 2 giving them a full outer shell and because their outer shell is stable they dont need to give up or gain electrons to become more stable
