Structure of atom and Language of Chemistry

Which sign is used to indicate the direction of the chemical reaction?

• Less than sign

• greater than sign

• arrow sign

Which of the following is not a feature of a chemical reaction?

• Evolution of gas

• occurrence of rain

• absorption of heat

Which of the following is formed when lead acetate is reacted with potassium iodide?

• Yellow precipitate

• green precipitate

• brown precipitate

• white precipitate

H₂ + Cl₂ gives out

• two atoms of Chlorine

• two molecules of Hydrochloric acid

• two molecules of water

Which gas is released when sodium carbonate reacts with dilute Hydrochloric acid?

• Hydrogen

• Oxygen

• Carbon dioxide

What are the negatively charged particles of an atom called as?

• protons

• neutrons

• electrons

Protons and neutrons are collectively called as ___________

• molecules

• electrons

• nucleons

Which of the following has variable valency?

• Sodium

• Potassium

• Iron

Which of the following are neutral?

• radicals

• electrons

• neutrons

It is also known as the core of an atom

• nucleus

• orbit

• radical