Period 3

Question 1

State and explain the general trend in first ionisation energy’s across period three[4 marks]

Answer 1

Overall there is a general increase
As There is a greater nuclear charge due to more protons
However the same amount of shedding/ electrons are added to the same shell
Therefore a stronger attraction from the nucleus

Question 2

Give one example of an element in period three which deviates from the general trend in first ionisation energy across period three
Explain why this deviation occurs

Answer 2

Aluminium
The outer electron is in the 3P orbital (a different shell)
That is higher in energy

Question 3

A student identified the burette as the largest source of uncertainty in the experiment
Using the same apparatus, suggest how the procedure could be improved to reduce the percentage uncertainty of The burette
Justify your suggestion
[2 marks]

Answer 3

Use a larger mass of solid or use a more concentrated solution
So a larger reading will be needed

Question 4

Element X forms an oxide that has a low melting point. This oxide dissolves in water to form an acidic solution

Deduce the type of bonding in this oxide of X

Answer 4

Covalent bonding

Question 5

Element X forms an oxide that has a low melting point. This oxide dissolves in water to form an acidic solution

Identify element X

Answer 5

Phosphorous

Question 6

Element X forms an oxide that has a low melting point. This oxide dissolves in water to form an acidic solution

Write an equation for the reaction between this oxide of X and Water

Answer 6

P4H10 + 6H2O —) 4H3PO4

Question 7

Element Y reacts vigorously with water. An oxide of Y dissolves in water to form a solution with a PH of 14

Deduce the type of bonding in this oxide of Y

Answer 7

Ionic bonding

Question 8

Element Y reacts vigorously with water. An oxide of Y dissolves in water to form a solution with a PH of 14

Identify element Y

Answer 8

Sodium

Question 9

Element Y reacts vigorously with water. An oxide of Y dissolves in water to form a solution with a PH of 14

Write an equation for the reaction of element Y with water (sodium)

Answer 9

2Na + 2H2O —) 2Na+ + 2HO- + H2

Question 10

What type of bond do all acids have ??

Answer 10

Covalent bonds

Question 11

What type of bond does all acids have ???

Answer 11

Ionic bonds

Question 12

Element Z forms an amphoteric oxide that has a very high melting point

Deduce the type of bonding in this oxide of Z

Answer 12

Ionic bonding

Question 13

Element Z forms an amphoteric oxide that has a very high melting point

Write the formula for this amphoteric oxide

Answer 13

Al2O2

Question 14

State the meaning of the term amphoteric

Answer 14

It reacts with acids and bases