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C3 Elements and compounds - Coggle Diagram
C3 Elements and compounds
Physical properties of the Group I metals
Are soft and easy to cut, getting softer and denser as you move down the Group (sodium and potassium do not follow the trend in density)
Have shiny silvery surfaces when freshly cut
Conduct heat and electricity
They all have low melting points and low densities and the melting point decreases as you move down the Group
The group I metals
The Group I metals are also called the alkali metals as they form alkaline solutions with high pH values when reacted with water
Group 1 metals are lithium, sodium, potassium, rubidium, caesium and francium
They all contain just one electron in their outer shell
Reactivity in Group I
The reactivity of the Group 1 metals increases as you go down the group
Each outer shell contains only one electron so when they react, they lose the outer electron which empties the outermost shell
The next shell down automatically becomes the outermost shell and is already full, hence the atom obtains an electronic configuration which has a full outer shell of electrons
As you go down Group 1, the number of shells of electrons increases by 1 (Period number increases down the Periodic table)
This means that the outer electron is further away from the nucleus so there are weaker electrostatic forces of attraction
This requires less energy to overcome the electrostatic forces of attraction between the negatively charged electron and the positively charged nucleus
This allows the electron to be lost easily, making it more reactive as you go down the Group
Chemical properties of the Group I metals
They react readily with oxygen and water vapour in air so they are usually kept under oil to stop them from reacting
Group 1 metals will react similarly with water, reacting vigorously to produce an alkaline metal hydroxide solution and hydrogen gas
Group VII the halogens
These are the Group 7 non-metals that are poisonous and include fluorine, chlorine, bromine, iodine and astatine
Halogens are diatomic, meaning they form molecules of two atoms
All halogens have seven electrons in their outer shell
They form halide ions by gaining one more electron to complete their outer shells
Physical properties of the halogens
The density and melting and boiling points of the halogens increase as you go down the Group
At room temperature (20 °C), the physical state of the halogens changes as you go down the Group
Chlorine is a gas, bromine is a liquid and iodine is a solid
The halogens become darker as you go down the group
Chlorine is pale green, bromine is red-brown and iodine is black
Reactivity in Group VII
Reactivity of Group 7 non-metals increases as you go up the Group
Each outer shell contains seven electrons and when they react, they will need to gain one outer electron to get a full outer shell of electrons
As you go up Group 7, the number of shells of electrons decreases (Period number decreases moving up the Periodic Table)
This means that the outer electrons are closer to the nucleus so there are stronger electrostatic forces of attraction that attract the extra electron needed
This allows an electron to be attracted more readily, so the higher up the element is in Group 7 then the more reactive it is
The Group VII Inoble gases
The Noble gases are in Group VIII (or Group O) and have very low melting and boiling points
They are all monatomic, colourless gases
The Group 0 elements all have full outer shells
This electronic configuration is extremely stable so these elements are unreactive and are inert
Uses of noble gases
Helium is used for filling balloons and weather balloons as it is less dense than air and does not burn
Neon, argon and xenon are used in advertising signs
Argon is used to provide an inert atmosphere for welding
Argon is also used to fill electric light bulbs as it is inert