The hardest naturally occuring substance is:

1. graphite
2. iron
3. diamond
4. coal

The inert gas filled in electric bulbs is:

1. Helium
2. Argon
3. Neon
4. Both (1) and (3)

Fill in the blanks:

(a) …………… refers to the number of atoms in the molecule of an element.

(b) The most abundant element in the earth's crust is …………… .

(c) A metal which is a liquid at room temperature is …………… .

(d) The most abundant element in the atmosphere is …………… .

(e) A metal which is a poor conductor of electricity is …………… .

(f) A diatomic gaseous element is …………… .

(g) A liquid non-metal is …………… .

(h) Elements that do not react chemically are …………… .

(i) The Latin name of iron is …………… .

(j) The horizontal rows in the Periodic table are called …………… .

(k) The vertical columns in the Periodic table are called …………… .

Indicate whether the following statements are true or false.

(a) A compound is made up of just one kind of atom. ……………

(b) Metals reflect light and are good conductors of electricity. ……………

(c) Metals can be polished. ……………

(d) Elements are made up of compounds. ……………

(e) All elements are artificially prepared. ……………

(f) Molecules can exist independently. ……………

(g) Molecules combine to form atoms. ……………

(h) Noble gases are highly reactive. ……………

(i) Ozone is a triatomic molecule. ……………