(English Medium) ICSE Class 9 - CISCE Question Bank Solutions for Chemistry

What is the contribution of the following in atomic structure?
Democritus

What is an α (alpha) particle?

How are X-rays produced?

State one observation which shows that atom is not indivisible.

Name an element which does not contain neutron.

What do you think would be the observation of `alpha` particle scattering experiment if carried out on (i) heavy nucleus like platinum (ii) light nuclei like litheum.

How does the Modern atomic theory contradict and correlate with Dalton's atomic theory?

Why do they exist as monoatoms in molecules?

Match the atomic numbers 4, 14, 8, 15 and 19 with each of the following:

1. A solid non-metal of valency 3.
2. A gas of valency 2.
3. A metal of valency 1.
4. A non-metal of valency 4. 

Define the term:

orbit 

Five atoms are labeled A to E

(a) Which one of these atoms:

(i) contains 7 protons
(ii) has electronic configuration 2,7

(b) Write down the formula in the compound formed between C and D

(c) Predict : (i) metals (ii) non-metals 

Why do `""_17^35"CI"` and `""_17^37"CI"`  have the same chemical properties? In what respect do these atoms differ?

Explain fractional atomic mass. What is the fractional mass of chlorine?

Name the following:

An element having valency 'zero'

Name the following:

Metal with valency 2

Name the following:

Two atoms having the same number of protons and electrons but different number of neutrons.

Name the following:

The shell closest to the nucleus of an atom 

Give a reason

Physical properties of isotopes are different.

Give reason

Argon does not react.

Give reason

`""_17^35"CI"` and `""_17^37"CI"` do not differ in their chemical reactions.