English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

A man is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in : a village

The English name of an element is potassium, its Latin name will be :

The drawing shows a ship 800 m from a cliff. A gun is fixed on the ship. After 5 seconds the people at the front of the ship hear the sound of the gun again.

(a) What is the name of this effect ?
(b) What happens to the sound at the cliff ?
(c) How far does the sound travel in 5 seconds ?
(d) Calculate the speed of sound.

The scientist who proposed the first letter (or first letter and another letter) of the Latin or English name of
an element as its symbol, was :

The atoms of which of the following pair of elements are most likely to exist in free state ?

The speed of highly penetrating ultrasonic waves is :

The symbols of the elements cobalt, aluminium, helium and sodium respectively written by a student are as
follows. Which symbol is the correct one ?

The atomic number of an element X is 13. What will be the number of electrons in its ion X3+ ?

The anion of an element has ______.

An element which can exhibit valencies of 2, 4 and 6 can be :

Two elements X and Y have valencies of 5 and 3, and 3 and 2, respectively. The elements X and Y are most likely to be respectively :

The formula of the sulphate of an element X is X2(SO4)3. The formula of nitride of element X will be :

A student wants to have 3.011 × 1023 atoms each of magnesium and carbon elements. For this purpose, he will have to weigh :

Define atomic mass unit. What is its symbol ?

Out of ozone, phosphorus, sulphur and krypton, the elements having the lowest and highest atomicities are respectively :

Differentiate the following.

Farmyard manure and Sheep manure

The chemical symbol for sodium is

Which of the following would weigh the highest?

Mass of one atom of oxygen is

Which of the following symbols of elements are incorrect? Give their correct symbols

1.  Cobalt CO
2. Carbon c
3. Aluminium AL
4. Helium He
5. Sodium So