Chapter 2 · Prerequisite 1 of 2Basics for textbook pages 23–42

Elements, Symbols, Metals and Non-metals മൂലകങ്ങൾ

The periodic table (പീരിയോഡിക് ടേബിൾ) is a chart of all the elements. Each box in it shows a symbol, and the colours tell you whether an element is a gas, a liquid or a solid. The chapter also sorts elements into metals, non-metals and metalloids. This page builds all of these ideas from zero. You will learn how an element differs from a compound and how symbols are made, including the strange ones like Na, K and Fe that come from Latin. You will test samples to tell metals from non-metals, and find which elements are solid, liquid or gas at room temperature.

📖 What you need

Nothing from earlier classes – every idea is built up here.
If you studied Chapter 1 (Structure of the Atom), this page is a quick revision. Still try the labs and the quiz.

1. Elements and compounds

Everything around you is made of tiny particles called atoms (ആറ്റം). There are only 118 kinds of atoms, and each kind is one element (മൂലകം).

Kind of substance	What it is made of	Examples
Element മൂലകം	Only one kind of atom. It cannot be broken down into simpler substances by chemical means.	Hydrogen, oxygen, carbon, iron, copper, gold, helium
Compound സംയുക്തം	Two or more different elements chemically joined in a fixed ratio. Its properties are quite different from those of its elements.	Water H₂O, carbon dioxide CO₂, common salt NaCl, copper sulphate CuSO₄

Common salt shows how different a compound can be. Sodium is a soft metal that reacts violently with water, and chlorine is a poisonous green gas. Joined together they make the salt you put on your rice! The quickest test is to read the formula: count how many different symbols it has. One kind of symbol means an element; two or more means a compound.

🧪 Element or compound? Read the formula

substance

Your answer:

Watch the capital letters: each capital starts a new symbol. Co is one symbol (cobalt, an element), but CO is two symbols, C and O (carbon monoxide, a compound). The balls are a code: real atoms have no colour.

2. Symbols of the elements

Writing “aluminium” or “phosphorus” again and again is slow, so every element has a short symbol (പ്രതീകം) of one or two letters. Every chemist in the world uses the same symbols.

One letter: the capital first letter of the name – H hydrogen, C carbon, N nitrogen, O oxygen.
Two letters: when several names start with the same letter, a second letter from the name is added – C carbon, Ca calcium, Cl chlorine, Cr chromium, Co cobalt, Cu copper.
The first letter is always a capital and the second is always small: Mg, not MG or mg.
A few symbols come from old names, mostly Latin. That is why sodium is Na and not So. Your periodic table (Fig 2.1) prints these old names in brackets.

🎬 Step by step · six elements that start with C

⚠ Capitals change the meaning

Co = cobalt (an element). CO = carbon monoxide (a compound of carbon and oxygen). Sn = tin, but SN would mean sulphur and nitrogen. Write symbols carefully in the exam.

🔎 Symbol explorer – the first 36 elements

Click any tile. The tiles are in order of atomic number, the small number in the corner (you will meet it on the next page). They are not yet arranged as the periodic table – that comes on page 5.

🎮 Symbol game

game

Questions come from the first 36 elements. Wrong options are chosen to look alike (same first letter), so read carefully.

3. Metals, non-metals and metalloids

Elements can also be sorted by how they look and behave. Your textbook uses three classes: metals (ലോഹങ്ങൾ), non-metals (അലോഹങ്ങൾ) and metalloids (ഉപലോഹങ്ങൾ).

Property	Metals ലോഹങ്ങൾ	Non-metals അലോഹങ്ങൾ
Look (lustre)	Shiny when freshly cut or polished	Usually dull
Hammering	Malleable: they flatten into sheets. Ductile: they can be drawn into wires.	Brittle if solid: they break into pieces
Heat and electricity	Good conductors	Poor conductors (insulators)
When struck	Sonorous: they ring	Not sonorous: a dull thud
State at room temperature	Solids (except mercury, a liquid)	Solids or gases (bromine is a liquid)
Examples	Iron, copper, aluminium, gold, silver, sodium, magnesium	Hydrogen, carbon, nitrogen, oxygen, sulphur, chlorine, iodine

Metalloids (ഉപലോഹങ്ങൾ) show both metallic and non-metallic nature. Silicon, for example, is shiny like a metal but brittle like a non-metal, and it conducts electricity only a little. That “a little” is what makes silicon chips in phones and computers possible. Common metalloids are boron, silicon, germanium, arsenic, antimony and tellurium.

🏠 Kerala connection

The copper uruli and the bell-metal (ഓട്) nilavilakku in your home are metals (bell metal is a mixture of copper and tin). They shine when polished and ring when tapped. Gold from the jewellery shops of Thrissur is beaten into thin sheets and drawn into fine wires because it is very malleable and ductile. Copper is used for electric wires because it conducts so well.

🔨 Virtual property tester

sample

Test:

Sample	Shine	Hammer	Conducts?	Rings?	Verdict

Do all four tests on each sample to fill your results table. Look out for the exceptions: graphite (pencil lead) is a form of carbon, a non-metal, yet it conducts electricity, and iodine crystals are shiny. One test alone can mislead – use all of them. (A simulation: the page makes no sound.)

⚠ Iodine and sulphur are handled by your teacher only, and you should never taste or smell chemicals directly. Sodium and potassium are metals so reactive that they are kept under kerosene; they react violently with water.

4. Solid, liquid or gas?

At room temperature (about 25 °C) an element is a solid (ഖരം), a liquid (ദ്രാവകം) or a gas (വാതകം). It depends on two temperatures:

Below its melting point an element is a solid: its particles only vibrate in fixed places.
Between its melting point and its boiling point it is a liquid: its particles stay close but slide past one another.
Above its boiling point it is a gas: its particles fly about freely and fill the container.

🌡️ Heat it up, cool it down

element temperature

Melting and boiling points are rounded (approx.). Each element's slider range changes so that both points fit. Only two elements are liquid at 25 °C: bromine (a non-metal) and mercury (a metal). Gallium and caesium melt at about 30 °C and 28 °C, just above room temperature. Gallium melts in your hand, so your textbook's table colours them, together with francium, as liquids.

5. The first 36 elements at a glance

Here are the same 36 tiles again. Switch the colours to see which are metals, non-metals and metalloids, and which are solid, liquid or gas. Notice that most elements are metals, and that the gases are all non-metals.

🗂️ Sort the first 36 elements

colour by

Think. Among the first 36 elements, is there any metal that is a gas?

No. Every gas among them – hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon and krypton – is a non-metal. In fact no metal is a gas at room temperature.

⭐ Key ideas

An element (മൂലകം) has one kind of atom; a compound (സംയുക്തം) has different elements joined in a fixed ratio.
A symbol (പ്രതീകം) has one or two letters: a capital first letter and a small second letter. Na, K, Fe, Cu, Ag, Sn, Sb, W, Au, Hg and Pb come from old (mostly Latin) names.
Metals (ലോഹങ്ങൾ) are shiny, malleable, ductile, sonorous and good conductors. Non-metals (അലോഹങ്ങൾ) are usually dull, brittle and poor conductors. Metalloids (ഉപലോഹങ്ങൾ) show both natures.
At room temperature most elements are solids. Bromine and mercury are liquids. Eleven are gases, all of them non-metals.

6. Check yourself

Next: Atom recap: atomic number, shells and electron configuration ▶