grade 7 revision

Potential energy of body depends on --------and------------------

Helium molecule consists of -------atom while hydrogen molecule consists of -----atom

The -----------and -------------solutions are good conductors of electricity

-------- is permanent resource of energy

An alloy of --------------is used in making jewels

but an alloy of ----------- is used in heating coils.

Solar heater changes ---------energy to ------------energy

Give reasons for:

The atom is electrically neutral.

Give reasons for:

Some birds have wide indented beaks

Write the chemical symbol for each:

I. Potassium.

2. Iron.

3. Carbon.

4. Oxygen

From the substances that float on water is

a. iron.

b. oil.

c. copper.

d. aluminum.