periodicity group 3

Question 1

define periodicity

Answer 1

pattern in properties across a row which is repeated in each row

Question 2

explain trend in BP with P,S,Cl and Ar

Answer 2

p4. the larger the molecule the more van der waals s8 cl2 Ar

Question 3

explain the trend in electronegativity across a period

Answer 3

• more protons in the nucleus - smaller atomic radius - stronger attraction between nucleus and 2 electrons in a covalent bond

Question 4

explain the trend in melting and boiling points in period 3

Answer 4

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

Question 5

explain the structure and bonding in sodium

Answer 5

mettalic lattice

• very soft metal
• stred under oil to prevent reaction with oxygen or watee vapour

Question 6

explain the observations of water and sodium

Answer 6

• 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

Question 7

explain the observations between sodium and oxygen

Answer 7

burns with a yellow orange flame to produce a white powder and smoke

Question 8

explain the structure and bonding of magnesium

Answer 8

metallic

Question 9

explain the observations of magnesium in water

Answer 9

• 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

Question 10

whats the equation of water and magnesium

Answer 10

balance this

Question 11

explain the structure and bonding of aluminium

Answer 11

metaliic , 3+ ions

Question 12

explain the observations with oxygen and aluminium

Answer 12

only will react as a powder

• needs an independant oxygen supply
• increased SA to react as a powder
• white powder and flame

Question 13

explain the structure and bonding of silicon

Answer 13

simple covalent molecular

Question 14

explain the observations between the reaction between silicon and oxygen

Answer 14

white flame and powder

• even in undependant oxygen supply it needs to be ignited to start reaction
• add Mg to help start the reaction

Question 15

explain the structure and bonding in phosphorus

Answer 15

simple covalent molecular

Question 16

explain the observations between phosphorus with oxygen

Answer 16

burns very well with oxygen

• stored underwater as reacts so well

Question 17

explain the structure and bonding of sulfur

Answer 17

simple covalent molecular

Question 18

explain the observations between sulfur and oxygen

Answer 18

bright blue flame

• chocking gas produced

Question 19

explain the structure and bonding of chlorine

Answer 19

simple covalent molecular

Question 20

explain the observations between chlorine and water

Answer 20

dissolves into very pale green solution

• produces chloric acid

Question 21

what do metal oxides form with water

Answer 21

base (alkali if reacts with water)

Question 22

what do non metal oxides form water

Answer 22

acids

Question 23

explain the structure of Na2O

Answer 23

giant ionic lattice

• very strong ESFOA between oppositelt charged ions

Question 24

explain the observations between Na2O and water

Answer 24

• splits into its ions which dissolve
• oxygen ions react with water to give OH- ions
• gives sodium hydroxide with a solution pH of 14

Question 25

explain the reaction of sodium oxide and acid

Answer 25

neutralises as it is a base -products are water and a salt

Question 26

explain the structure of MgO

Answer 26

- giant ionic lattice - Mg is a 2+ , smaller ion and very charge dense - very high BP and lattice enthalpy

Question 27

explain the observations of magnesium oxide and water

Answer 27

- only slightly soluble as the lattice is too strong gives a pH of 10 as doesnt dissolve too well

Question 28

give the equation between MgO and acid

Answer 28

Question 29

explain the structure of Al2O3

Answer 29

- giant ionic lattice - insoluble due to strong bond enthalpy as Al forms 3+ ions

Question 30

give the reaction between aluminium oxide and acid

Answer 30

amphotenic, acts as a acid and a base

Question 31

give the equation between aluminium oxide and alkali

Answer 31

Question 32

explain the structure of Si2O

Answer 32

giant covalent insoluble due to many strong covalent bonds need to be broken

Question 33

give the reaction between SiO2 and alkali

Answer 33