Atomic radius
the distance between the nucleus and the outermost electron of an atom
what happens to the atomic radius across the period?
Across the period the proton number increases meaning that the nucleus attracts the electrons more strongly pulling them closer to the nucleus, decreasing the atomic radius
what is an ionic radius?
the distance between nucleus and the outermost electron of an ion
electrical conductivity
refers to how well a substance can conduct electricity
How are Na, Mg & Al arranged?
they are metallic elements which form giant metallic lattices of positive ions arranged in a regular lattice in which the ions are held together by a sea of mobile electrons around them.
Why does silicon have a high melting point?
Due to its giant molecular structure and strong covalent intermolecular forces
what is the structure of P, S, Cl & Ar
simple covalent
What happens to the electrical conductivity across period 3
decreases
what is the flame of combustion of Na?
Bright Yellow
What is the flame colour of combustion of Mg?
Bright White
What is the flame colour of combustion of Al?
Bright White
What is the flame colour of combustion of Si?
Bright white sparkles
What is the flame colour of combustion of S?
Blue
How does sodium react with cold water?
vigorously, it melts into a ball and moves across the water and then dissolving
Magnesium reaction with cold water
extremely slowly
Why are giant ionic and giant covalent structured oxides difficult to break?
because they have high melting points
What do oxides of Na and Mg which have ionic bonding produce with water?
alkaline solution with water as their oxide ions become OH-
What do oxides of P and S which have covalent bonding produce with water?
acidic solutions because when their oxides react with water they donate H+ ions
Do NaCl & MgCl react with water?
no because water is polar
What are the two forms of Aluminium Chloride?
Anhydrous covalent AlCl3 and in aqueous solution which is dissolves into ions
What is electronegativity?
the power of an element to draw the electrons towards itself in a covalent bond
What happens to the electronegativity of when you go across period 3?
it increases
