Ionisation energy/grp 2

Question 1

State and explain the trend in atomic radius from Li to F 3

Answer 1

• from Li, to F, atomic radius decreases
• nuclear charge increases
• outer electrons experience similar shielding
• so greater nuclear attraction on outer shells

Question 2

State how and explain why the attraction between nuclei and outermost electrons in gaseous atoms varies across Period 3. 2

Answer 2

• attraction between nuclei an outermost electrons increases across a period and nuclear charge increases
• outer electrons experience similar shielding

Question 3

Why does P have higher mp than Cl 3

Answer 3

P has more electrons
stronger london forces
More energy required to break the intermolecular forces

Question 4

what is the shape around carbon atoms in graphene?

Answer 4

trigonal planar

Question 5

Why are silicon, carbon, oxygen and chlorine all classified as p-block elements?

Answer 5

highest energy electrons are in a p orbital

Question 6

Describe and explain the electrical conductivity of sodium oxide, Na2O, and sodium in their solid and molten states 5

Answer 6

• sodium conducts in solid and molten states
• as sodium has delocalised electrons in both solid and molten state
• Na2O conducts when molten and not when solid
• Molten Na2O has ions which are mobile
• Solid Na2O has ions which are fixed in position

Question 7

Explain why the first ionisation energy of strontium is less than the first ionisation energy of calcium 3

Answer 7

• larger atomic radius (more shells)
• increased nuclear charge outweighed by increased shielding
• so less nuclear attraction

Question 8

Describe what you would expect to see when magnesium ribbon is added to an
excess of dilute hydrochloric acid., and say how Sr would react differently

Answer 8

fizzes, mg dissolves

sr reacts quicker

Question 9

Write an equation, including state symbols, for the thermal decomposition of CaCO3

Answer 9

CaCO3 (s)-> CaO(s) + CO2(g)

Question 10

The student had added the exact amount of calcium required to react with the
hydrochloric acid used. After carrying out the experiment, the student accidentally
added some more calcium. The student was surprised that the extra calcium still
reacted.
Explain this observation. Include an equation in your answer

Answer 10

Ca reacts with water producing Hydrogen
Ca(s) + H2O(l) → Ca(OH)2
(aq) + H2
(g)

Question 11

State the formula of the calcium compound formed when

(i) calcium oxide reacts with water,
(ii) calcium oxide reacts with nitric acid.

Answer 11

i- Ca(OH)2

ii- Ca(NO3)2

Question 12

Old samples of magnesium oxide become contaminated with magnesium carbonate.
(i) Suggest how this contamination takes place.

Answer 12

When MgO has reacted with CO2

Question 13

explain with diagrams why resulting solution of MgO with contaminated MgCO3 contained only 1dissolved compound of magnesium 3

Answer 13

MgO + 2HCl → MgCl2 + H2O
MgCO3 + 2HCl → MgCl2 + CO2 + H2O
both reactions form magnesium chloride/MgCl2