End Of Unit Questions

Question 1

What are the names and numbers of the particles in an atom of sodium (atomic number 11, mass number 23)?

Answer 1

Protons = 11
Neutrons = 12 
Electrons = 11

Question 2

What determines the order of the elements in the periodic table?

Answer 2

Each elements proton number

Question 3

Explain why boron and aluminium are both in the same group in the periodic table

Answer 3

They both have 3 electrons in their outer shells

Question 4

Explain what happens to the atoms when a sodium atom reacts with a chlorine atom

Answer 4

Sodium atom loses an electron and becomes positive sodium ion, chlorine gains an atom gains an electron and becomes negative chlorine ion

Question 5

Calcium carbonate decomposes when heated to produce calcium oxide and carbon dioxide. 20g of calcium carbonate produced 11.2g of calcium oxide, what mass of carbon dioxide would be produced?

Answer 5

8.8g

Question 6

Balance these symbol equations
•Ca + O2 –> CaO
•Na + H2O –> NaOH + H2
•CH4 + O2 –> CO2 + H2O

Answer 6

• 2Ca + O2 –> 2CaO
• 2Na + 2H2O –> 2NaOH + H2
• CH4 + 2O2 –> CO2 + 2H2O

Question 7

Sort these substances into elements and compounds and molecules: 
•Ca
•CH4 
•H2 
•HCl 
•MgO
•Ne
•O2 
•SO2

Answer 7

Elements: 
•Ca
•Ne
Compounds:
•MgO
Molecules: 
•CH4
•H2
•HCl
•O2
•SO2