Write the names of the planets (Greek God) after which these elements are named.

a) Plutonium b) Neptunium c) Uranium

Water is made up of two elements, hydrogen and oxygen. Water is a liquid, whereas hydrogen and oxygen are gases. Hydrogen catches fire easily. Oxygen helps in burning. Water is used to put off the fire.

From the above information, answer the following questions.

a) What are the elements present in water?

b) In which state do these elements exist?

c) Write the property of hydrogen.

d) Write the property of oxygen.

e) Do the properties of water differ from hydrogen and oxygen?

Using the elements enclosed in the bottle, frame formulae for some compounds.

Find the valency of the underlined element in the given formulae.

i) H₂O ii) KCl iii) Al₂O₃ iv) Fe₂O₃ v) CH₄

Write the chemical name of the given formulae.

i) MgO ii) HCl iii) NH₃ iv) ZnO v) NaCl