Class 9 Paper Test

Select the chemical formula of Sodium Oxide.

• SOO

• Na₂O

• NAO

• Nao

CO represents

• an element

• a compound

• a mixture

• none of the above

On the room temperature .............. (name of the element) exits on liquid state.

• mercury

• gold

• water

• wax

Calculate the molecular mass of H₂CO_3, Given H= 1 amu, C 12 amu, O 16 amu

• 60

• 61

• 62

• 63

An element has 12 proton and 13 neutron, calculate the atomic mass of this element?

• 1

• 25

• 156

• none of the above

An atom is neutral because:

• It has equal no of proton and neutron

• It has equal no of electron and neutron

• It has equal no of proton and electron

• All of the above

Write down the chemical formula of Magnesium Hydroxide.

• Mg(OH)₂

• Mgoh₂

• MgOH

• MG(OH)₂

In an atom the number of proton is equals to

• neutron

• electron

• none of the above

• both A and B