1.2 Periodicity Of Physical Properties Flashcards
What is periodicity?
The repeating patterns in the physical and chemical properties of the elements across the periods of the periodic table
What happens to the atomic radii across the period?
It decreases because of the increasing positive nuclear charge that pulls the electrons in outer shells closer to the nucleus.
What is the periodic pattern of ionic radii?
The ionic radius decreases across the period as the positive charge on the iron increases and the negative charge on the ion decreases.
Why do negative ions have larger ionic radii than positive ions in the same period?
Because they have one more electron shell, so the outer electrons are further from the nucleus and there’s more shielding
Describe the pattern of electrical conductivity in the third period
The electrical conductivity increases from sodium in group one to aluminium in group 13. The electrical conductivity then drops dramatically just silicon which is described as semiconductor and fall even further across the period.
Why does the electrical conductivity increase from group one to group 13 in period three?
Because across the period from group one to group 13, the number of delocalised electrons per atom increases which means there will be more free atoms to drift through the metal towards the positive terminal when potential difference is applied to it
Why does the melting point increases across the period from group 1 to group 13?
Because moving across the period from group 1 to group 13, the metals will have more delocalised electrons therefore a stronger metallic bonding
Why do group 14 elements have a high melting point?
Because they have giant covalent structures
Sulphur phosphorus and chlorine molecules exist as
S8, P4, Cl2
What happens when sodium reacts with oxygen?
Sodium react vigourously when heated and placed in a gas jar of oxygen. The sodium burns with a bright yellow of flame. The main product when sodium burns in the limited amount amount of oxygen is a white solid sodium oxide.
What happens when magnesium reacts with oxygen?
Magnesium also reacts vigourously reacted with oxygen forming magnesium oxide
How does aluminium react with oxygen?
Aluminium metal is protected by a layer of aluminium oxide but powdered aluminium does react well with oxygen both aluminium and oxygen burn with bright white flames
How does silicon react with oxygen?
Silicon reacts slowly with oxygen to form silicon oxide
How does phosphorus react with oxygen?
Yellow or white flame is seen and clouds of white phosphorus oxide produced
How does sulphur react with oxygen?
Burns gently with a blue flame. Toxic fumes of sulphur dioxide produced.
Further oxidation of sulphur dioxide sulphur dioxide. Systematic or sulphur four oxide and sulphur oxide respectively.
