Which of the following ores is in the form of carbonate?

Write the electron-dot structure for sodium and chlorine atoms. How do these form a chemical bond? Name the type of bond so formed. Why does a compound so formed have a high melting point?

Which kind of impurities are present in the ores? What are these impurities collectively known as?

Which compound is formed when dinitrogen gas reacts with dihydrogen gas?

Which of the following non-metals exists in a solid state at room temperature?

Explain the following statements:
$(a)$ Most metal oxides are insoluble in water but some of these dissolve in water. What are these oxides and their solutions in water called?
$(b)$ At ordinary temperature,the surfaces of metals such as magnesium,aluminium,and zinc are covered with a thin layer. What is the composition of this layer? State its importance.
$(c)$ Some alkali metals can be cut with a knife.