3.1 The Periodic Table

Question 1

what is the arrangment of atoms

Answer 1

from left-> right, increasing atomic number
in groups, with the same outer shell and similar properties
in periods (horizontal) with the number giving the highest electron shell in the elements atoms

Question 2

what is ionisation energy

Answer 2

how easily an atom loses its electrons

Question 3

what must happen for first ionisation energy

Answer 3

must be in the highest energy level and have the least attraction

Question 4

what are factors affecting ionisation energy

Answer 4

atomic radius- the greater the distance, the less attraction
nuclear charge- more protons=more attraction
electron shielding- - charged, so inner repel outer and the repulsion will reduce the attraction

Question 5

what is the trend in 1st ionisation energies down a group

Answer 5

decreases

as the radius increases, shielding increases and nuclear attraction on outer electrons decreases

Question 6

what is the trend in 1st ionisation energy across a period

Answer 6

increases
as nuclear charge increases, has similar shielding (same shell), nuclear attraction increases and atomic radius decreases

Question 7

what is metallic bonding

Answer 7

is the strong electrostatic attraction in metals
in a solid metal, each atom has donated its outer shell electrons to a shared pool of electrons that are delocalised
cations (positive) are fixed
anions (negative) are delocalised

Question 8

why do metals have a high MPT and BPT

Answer 8

high temps are required to break the strong electrostatic attraction between cations and electrons

Question 9

why are most metals good conductors

Answer 9

in solid and liquid states

delocalised electrons move and so could carry the charge

Question 10

why are metals insoluble

Answer 10

any interactions lead to a reaction

Question 11

what are giant covalent lattices

Answer 11

• boron, carbon and silicon form a network of strong covalent bonds
• carbon (in diamond form) and silicon use their 4 outer electrons to bond to other carbons and silicons
  is tetrahedral
  109.5

Question 12

what are the MPT and BPT of giant covalent lattices

Answer 12

high because they are strong

Question 13

what is the solubility of giant covalent lattices

Answer 13

insoluble in most solvents as the bonds are far too strong

Question 14

electron configuration of period 2 elements

Answer 14

Atoms of group 2 have 2 electrons in their outer shell and readily form 2+ ions that have the same electron configuration as a noble gas

Question 15

physical properties of group 2

Answer 15

All metals and so are good conductors of electricity and have high melting and boiling points.
Form colourless ionic compounds ( with the exception of beryllium) that also have high melting and boiling points. The compounds are good conductors when molten or in aqueous solution.

Question 16

chemical properties of group 2

Answer 16

React by losing 2 electrons. Give up their s electrons to form M2+ ions, witch are isoelectric with a noble gas
M → M2+ + 2e-
Are reducing agents

Question 17

trend of reactivity of group 2

Answer 17

Increases down the group and barium is the best reducing agent. Reactivity can be explained in terms of ease in which they lose electrons

Question 18

how does group 2 react with oxygen

Answer 18

Undergo redox reactions with oxygen. Apart from beryllium, they burn brightly in oxygen to form ionic oxides ( M2+O2-)
All oxides, apart from BeO are all white solids with high melting points that react with water to form solutions of the corresponding hydroxides. The oxides are all basic oxides and react with acids to form salts.

Question 19

magnesium with oxygen

Answer 19

bright white flame
Mg(s) + ½ O2(g) → MgO (s)
melting point- 2852

Question 20

calcium with oxygen

Answer 20

brick-red flame
Ca(s) + ½ O2(g) → CaO (s)
melting point- 2614

Question 21

strontium with oxygen

Answer 21

crimson flame
Sr(s) + ½ O2(g) → SrO (s)
melting point- 2430

Question 22

barium with oxygen

Answer 22

green flame
Ba(s) + ½ O2(g) → BaO (s)
melting point- 1918

Question 23

what is the reaction of group 2 with chlorine

Answer 23

All group 2 metals react with chlorine to form white chlorides
M(s) + Cl2(g) → MCl2(aq) + H2(g)

Question 24

what is group 2 reaction with water

Answer 24

M(s) + 2H2O(l) → M(OH)2(s) + H2
Magnesium reacts very slowly with water and Mg(OH)2 formed is a white precipitate
Mg(s) + 2H2O(l) → Mg(OH)2(s) + H2
Magnesium reacts more readily on heating with steam to form the oxide
Mg(s) + 2H2O(g) → MgO (s) + H2 (g)
The oxidation number of the group 2 element increases from 0 to +2 and the oxidation number of hydrogen changes from +1 to 0

Question 25

what is electron configuration of the halogens

Answer 25

Atoms of group 17 have 7 electrons in their outer shell and readily form 1- ions that have the same electron configuration as a noble gas

Question 26

what is the physical properties of the halogens

Answer 26

Are non-metals and so are poor conductors
At room temperature, fluorine is a yellow gas, chlorine is a green gas, bromine is a dark red/brown gas and iodine is a grey/black solid that sublimes to form a purple/violet gas
from fluorine to iodine, there is an increase in induced dipole-dipole interactions, corresponding to the increased number of electrons, reduces volatility, so melting and boiling point increases down the group

Question 27

what is bromines reactivity

Answer 27

Is reactive but is a less powerful oxidising agent than chlorine. Used to make a range of products such as flame retardants and medicines

Question 28

what is fluorine’s reactivity

Answer 28

Fluorine is most electronegative and it’s a powerful oxidising agent. Oxidation state is -1 in all its compounds. Uses include the manufacture of a range of compounds consisting of only carbon and fluorine

Question 29

what is chlorines reactivity

Answer 29

Reacts directly with most elements. In its compounds, it is usually present in -1 oxidation state but can be oxidised to positive oxidation states by oxygen and fluorine. Used in the production of polymers such as polyvinylchloride (PVS). Water companies use chlorine to kill bacteria in drinking water. Used to bleach paper and textiles

Question 30

what is iodine’s reactivity

Answer 30

Is an oxidising agent but not as powerful as the others. Used in a range of products such as dyes and catalysts. Needed in diet so thyroid gland can make thyroxine which regulates growth and metabolism

Question 31

what is chemical properties of the halogens

Answer 31

React by gaining electrons to form halide anions. The ease at which electrons is gained decreases as atomic radius and shielding decreases down a group, reducing the attraction of the nucleus for electrons.
Halogens react directly with:
Metals: 2Na(s)+ Cl2(g) → 2NaCl(s)
Fe(s) + Cl2(g) → FeCl(s)
Non-metals: Si(s) + 2Cl2(g) → SiCl4(l)
P4(s) + 10Cl2(g) → 4PCl5(l)
Chlorine doesn’t react directly with carbon, oxygen or nitrogen

Question 32

what is the disproportionation reactions of the halogens

Answer 32

[see physical flashcards]

Question 33

what is chlorine in water treatment

Answer 33

Reacts reversibly with water and the resultant mixture kills bacteria 
Cl2(aq) + H2O(l) ⇌ HCl(aq) + HClO(aq)
Reaction is redox. 
1 chlorine is oxidised (0→+1) 
1 chlorine is reduced (0→-1)

Question 34

what is the benefits and risks of chlorine in water treatment

Answer 34

Reduces risk of waterborne disease such as cholera and typhoid fever. Chloric (i) acid molecules are able to pass through cell walls of bacteria and once inside, HClO molecules break up and kill organism but oxidising and chlorinating molecules that make up the cell structure.
Can produce harmful by-products i.e. traces of chlorinated hydrocarbons such as trichloromethane

Question 35

what is the test for halogens

Answer 35

Silver chloride, silver bromide and silver iodide are insoluble in water. So add to an aqueous solution of silver nitrate. First acidified by dilute nitric acid and silver nitrate is added.
Ag+ + X- → AgX(s)

Question 36

how to tell for silver chloride

Answer 36

Silver chloride- white precipitate that turns grey in sunlight.
Dissolved in dilute ammonia

Question 37

how to tell for silver bromide

Answer 37

Silver bromide- cream precipitate that darkens in sunlight.

Dissolves in concentrated ammonia

Question 38

how to tell for silver iodide

Answer 38

Silver iodide is a yellow precipitate