Question

Ques1. Fill in the blanks with correct word: (5)
(a) A symbol represents a short form of an ___________
(b) A chemical equation is a shorthand form for a ________ change
(c) Direct combination of sulphur dioxide with water gives _________ acid
(d) The neutral gas evolved when lead nitrate undergoes thermal decomposition is ___________
(e) Variable valency is shown since electrons are lost from an element from the _______ shell

Answer 1

Explanation:

a) element

b) chemical

c) sulphuric

e) orbit

sorry!! I don't know exact answer of d part

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Answer 2

Answer:

1. An element's symbol is merely a shorthand representation of the element. It would be painstaking to have to write out the name of the element every time you wanted to mention it, so the symbols are a great way to shortly represent the element!
2. chemical reaction is typically represented by a chemical equation, which represents the change from reactants to products. The left hand side of the equation represents the reactants, while the right hand side represents the products
3. Sulphur dioxide dissolves in water to produce Sulphurous acid which dissociates to make the water acidic. Sulphur dioxide can dissolve in water to form Sulfurous acid(H2SO3).
4. Oxygen
5. When lead nitrate undergoes thermal decomposition, the neutral gas evolves is Oxygen . So, in the decomposition process both oxygen and Nitrogen Dioxide gas is evolved. However, NO2 is an acidic oxide and forms nitric acid with water..
6. Answer is penultimate shell . variable valency is generally shown by d-block element( transition elements) , in transition elements, an atom loses electrons from the shell next to the valence shell (penultimate shell).