periodicity group 3 Flashcards
define periodicity
pattern in properties across a row which is repeated in each row
explain trend in BP with P,S,Cl and Ar
p4. the larger the molecule the more van der waals s8 cl2 Ar
explain the trend in electronegativity across a period
- more protons in the nucleus - smaller atomic radius - stronger attraction between nucleus and 2 electrons in a covalent bond
explain the trend in melting and boiling points in period 3
metals = increase as go along due to higher charge on the ions, higher ESFOA between ions and delocalised es, smaller and more charge dense
Si= high increase due to being a giant covalent lattice, many strong covalent bonds
P+S+Cl = simple moleculae, depends on p4 S8 and Cl2 , van der waals
Ar= monatomic
explain the structure and bonding in sodium
mettalic lattice
- very soft metal
- stred under oil to prevent reaction with oxygen or watee vapour
explain the observations of water and sodium
- floats and moves on the water and fizzes
- burns with a yellow/orange flame
- ball of ‘liquid’ metal as the reaction is so exothermic energy is released and melts to a sphere
- hydrogen gas released by displacement
- sodium hydroxide made
explain the observations between sodium and oxygen
burns with a yellow orange flame to produce a white powder and smoke
explain the structure and bonding of magnesium
metallic
explain the observations of magnesium in water
- does not react with cold water
- magnesium needs to loose 2 electrons to react
- very slow reaction
- must react with steam to produce a white flame, hydrogen released, gives white powder
whats the equation of water and magnesium
balance this
explain the structure and bonding of aluminium
metaliic , 3+ ions
explain the observations with oxygen and aluminium
only will react as a powder
- needs an independant oxygen supply
- increased SA to react as a powder
- white powder and flame
explain the structure and bonding of silicon
simple covalent molecular
explain the observations between the reaction between silicon and oxygen
white flame and powder
- even in undependant oxygen supply it needs to be ignited to start reaction
- add Mg to help start the reaction
explain the structure and bonding in phosphorus
simple covalent molecular
explain the observations between phosphorus with oxygen
burns very well with oxygen
- stored underwater as reacts so well
explain the structure and bonding of sulfur
simple covalent molecular
explain the observations between sulfur and oxygen
bright blue flame
- chocking gas produced
explain the structure and bonding of chlorine
simple covalent molecular
explain the observations between chlorine and water
dissolves into very pale green solution
- produces chloric acid
what do metal oxides form with water
base (alkali if reacts with water)
what do non metal oxides form water
acids
explain the structure of Na2O
giant ionic lattice
- very strong ESFOA between oppositelt charged ions
explain the observations between Na2O and water
- splits into its ions which dissolve
- oxygen ions react with water to give OH- ions
- gives sodium hydroxide with a solution pH of 14
explain the reaction of sodium oxide and acid
neutralises as it is a base
-products are water and a salt
explain the structure of MgO
- giant ionic lattice
- Mg is a 2+ , smaller ion and very charge dense
- very high BP and lattice enthalpy
explain the observations of magnesium oxide and water
- only slightly soluble as the lattice is too strong
gives a pH of 10 as doesnt dissolve too well
give the equation between MgO and acid
explain the structure of Al2O3
- giant ionic lattice
- insoluble due to strong bond enthalpy as Al forms 3+ ions
give the reaction between aluminium oxide and acid
amphotenic, acts as a acid and a base
give the equation between aluminium oxide and alkali
explain the structure of Si2O
giant covalent
insoluble due to many strong covalent bonds need to be broken
give the reaction between SiO2 and alkali
