Define the following with examples- Roasting

Roasting is a process of extracting moderately reactive metals like zinc. In this, a sulphide ore is strongly heated in the presence of air to convert it into metal oxide. This also removes free sulphur, arsenic, etc. Therefore, the following reaction can be observed zinc sulphide is roasted to form zinc oxide and sulphur dioxide gas. 2 ZnS s Zinc Sulphide Zinc blende ore + 3 O 2 g Oxygen Excess air → Roasting 2 ZnO s Zinc oxide + 2 SO 2 g Sulphur dioxide

Define the following with examples- Calcination

Calcination is a process of extracting moderately reactive metals like zinc. In this, a carbonate ore is strongly heated in the absence of air to convert it into metal oxide. This also removes moisture and other volatile impurities. Therefore, the following reaction can be observed zinc carbonate is calcined to decompose into zinc oxide and carbon dioxide gas. ZnCO 3 s Zinc Carbonate Calamine ore → Calcination ZnO s Zinc oxide + CO 2 g Carbon dioxide

Those substances which are made by combining two or more metals or a metal and a non-metal and possessing the metallic character or desirable qualities of metals like hardness, lightness and strength is known as an alloy. They form homogeneous mixtures. They are more resistant to corrosion. For example- Steel, Brass, and, bronze. Brass is an alloy of two metals- copper and zinc. Steel or and stainless steel is an alloy of iron and carbon.

Give two differences between metals and non-metals.

Metals and non-metals can be differentiated as follows- Metals Non-Metals Metal reacts with water to liberate hydrogen gas. Non-metals do not react with water. Metals combine with oxygen and form basic oxides. These turns red litmus to blue. 4 Na + O 2 → 2 Na 2 O Non-metals combine with oxygen and form acidic oxides or neutral oxides. These turns blue litmus to red. C + O 2 → CO 2 Eg- Sodium, Potassium. Eg- Carbon, Sulphur.

How many maximum electrons may be in L-shell?

Electronic configuration is defined as the distribution of the electrons in the energy shells (K, L, M, N). According to Bohr-Bury theory, the maximum number of electrons that can be present in energy shells is given by 2 n 2 , where n is the number of energy shells. Therefore, the maximum number of electrons in L-shell is 8 . Electron shell calculation Maximum electrons K shell n = 1 no . of e - = 2 n 2 = 2 × 1 2 = 2 × 1 = 2 2 electrons L shell n = 2 no . of e - = 2 n 2 = 2 × 2 2 = 2 × 4 = 8 8 electrons M shell n = 3 no . of e - = 2 n 2 = 2 × 3 2 = 2 × 9 = 18 18 electrons N shell n = 4 no . of e - = 2 n 2 = 2 × 4 2 = 2 × 16 = 32 32 electrons

Which acids are used in preparation of aqua regia, and what are their proportion? Write one characteristic of Aqua regia.

Aqua-regia is prepared by fresh mixture of concentrated nitric acid and concentrated hydrochloric acid in 3 : 1 ratio respectively. It is highly corrosive, fuming liquid which can dissolve all metals like gold, platinum, etc. Due to its corrosive property, it can be used to clean glassware and refining gold metals.

Write electronic configuration(in shells) of following element- Na(11)

Electronic configuration is defined as the distribution of the electrons in the energy shells (K, L, M, N). According to Bohr-Bury theory, the maximum number of electrons that can be present in energy shells is given by 2 n 2 , where n is the number of energy shells. The atomic number of sodium is 11 . Therefore, the electronic configuration of sodium is 2 , 8 , 1 . Electron shell Shell Maximum electrons K shell Completely filled 2 electrons L shell Completely filled 8 electrons M shell Not filled 1 electron N shell - -

Write electronic configuration(in shells) of following element- Mg(12)

Electronic configuration is defined as the distribution of the electrons in the energy shells (K, L, M, N). According to Bohr-Bury theory, the maximum number of electrons that can be present in energy shells is given by 2 n 2 , where n is the number of energy shells. The atomic number of magnesium is 12 . Therefore, the electronic configuration of magnesium is 2 , 8 , 2 . Electron shell Shell Maximum electrons K shell Completely filled 2 electrons L shell Completely filled 8 electrons M shell Not filled 2 electrons N shell Empty No electrons

Write electronic configuration(in shells) of following element- Al(13)

Electronic configuration is defined as the distribution of the electrons in the energy shells (K, L, M, N). According to Bohr-Bury theory, the maximum number of electrons that can be present in energy shells is given by 2 n 2 , where n is the number of energy shells. The atomic number of aluminium is 13 . Therefore, the electronic configuration of aluminium is 2 , 8 , 3 . Electron shell Shell Maximum electrons K shell Completely filled 2 electrons L shell Completely filled 8 electrons M shell Not filled 3 electrons N shell Empty shell No electrons

What happens when Zinc Oxide is heated with carbon.(write only chemical equation)

Metal oxide is reduced by carbon to extract pure metal. Therefore, zinc metal is extracted by the reduction of zinc oxide with carbon or coke which acts as a reducing agent. The following chemical reaction will take place- ZnO s Zinc oxide + C s Carbon → Zn s Zinc metal + CO g Carbon monoxide