The electronic configurations of three elements X , Y and Z are: X ⇒ 2 , Y ⇒ 2 , 8 , 7 Z ⇒ 2 , 8 , 2 Which of the following is correct regarding these elements?

Y is a non-metal and Z is a metal

Corrosion is the damage caused to the metal by the chemical reaction of air, water and acids with the surface of the metal. Generally reactive metals corrode easily and non-reactive metals have good resistance to corrosion. For example, Copper reacts with moist carbon dioxide in the air and gets a green coat of copper carbonate.

Give the name and chemical formula of one ore of copper.

Copper glance is the name of the ore of copper and its chemical formula is Cu 2 S . It is a sulphide ore of Copper. Note: The main copper sulphide minerals are chalcopyrite ( CuFeS 2 ) chalcocite ( Cu 2 S ) , covellite ( CuS ) , bornite ( Cu 5 FeS 4 ) , tetrahedrite and enargite. The largest source of copper is from porphyry ore deposits in which one or a combination of the aforementioned minerals occurs.

Why do we apply paint on iron articles?

By painting the iron article we can prevent rusting. It prevents the contact of air and moisture with the iron that causes iron to rust. After painting iron surface does not come in contact with moisture and air which cause rusting.

Differentiate between metals and non-metals on the basis of their chemical properties.

Chemical properties of metals Chemical properties of non-metal Metals forms basic oxides. Non-metals forms acidic or neutral oxides. Chemical properties of metals Chemical properties of non-metal Metals displace hydrogen from water. Non-metals do not react with water. Chemical properties of metals Chemical properties of non-metal Metals displace hydrogen from dilute acids. Non-metals do not react with dilute acids.