Page 32 - ICSE Chemistry 6

Thirst for Knowledge
Bromine is the only liquid non-
metal (at room temperature).
Hydrogen and helium together
Mercury is the only liquid metal
account for about 99% of the mass (at room temperature).
of the known universe.
sulphur
Fig. 2.4: Non-metal

Proper es of Non-Metals

Either so Mostly bri le Do not possess Bad conductors Neither Low mel ng Not
solids or in nature shine or of heat and malleable nor and boiling sonorous
gases lustre electricity duc le points

Common Elements

In the universe In the earth’s crust In the atmosphere In the human body

Hydrogen and Oxygen in the greatest Nitrogen Carbon, hydrogen and oxygen
helium amount followed by silicon, make up the compounds in the
aluminium and iron cells of the body

Metalloids

Elements that possess the proper es of both metals and non-metals are called
metalloids.
Boron, silicon, arsenic and an mony are some metalloids. They are solid, shiny
or dull, duc le, malleable, and conduct heat and electricity be er than non-
metals but not as well as metals.
silicon
Noble (Inert) Gases Fig. 2.5: Metalloid

There are some elements that are present in gaseous state and do not react chemically with other
elements. Such elements are called noble (inert) gases. Helium, neon, argon, krypton, xenon and radon
are noble (inert) gases. These gases are present only in traces in air.

Activity 2.1

Aim: To study the symbols of fi rst 20 elements of the periodic table

Materials required: A periodic table
Procedure: See the given periodic table and study the symbols of the fi rst 20 elements shown. Tables 2.1,
2.2 and 2.3 show symbols of the fi rst 20 elements.

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