ELEMENTS ,COMPOUNDS AND MIXTURES

Question 1

Define an element.

Answer 1

Any pure substance which cannot be broken into two or more simpler substances by any
Chemical means is called an element.

Question 2

How many elements have been discovered so far? How many of the discovered
Elements are metals?

Answer 2

118 elements are discovered in which 80 are metals.

Question 3

What are a) Normal elements b) Harmful elements? Give two examples of each.

Answer 3

A) Normal elements:- By normal elements we mean such elements which do not give out
Any harmful radiation . There are 82 normal elements. Example : Fe ,Zn
B) Harmful elements:- By harmful elements we mean such elements which give out
harmful radiation. There are 36 harmful elements. Example : Radium, Uranium

Question 4

Define the term metal.

Answer 4

A Any element is a metal if it has lustre , is a good conductor of heat and electricity , is
Malleable and ductile and has high melting point and boiling point.

Question 5

Examples of metals.

Answer 5

Sodium Na Natrium
Potassium K Kalium
Gold Au Aurum
Iron Fe Ferrum
Copper Cu Cuprum