## Oxygen atom has 8 electrons,

[question] Question. Oxygen atom has 8 electrons, 8 protons and 8 neutrons whereas sulphur atom has 16 electrons, 16 protons and 16 neutrons. Find out the mass number of oxygen and sulphur atoms. [/question] [solution] Solution: Mass number of oxygen = Number of protons + Number of neutrons = 8 + 8 =16 Mass number of sulphur = Number of protons + Number of neutrons = 16 +16 = 32 [/solution]...

## If number of electrons in an atom is 8 and number of protons is also 8,

[question] Question. If number of electrons in an atom is 8 and number of protons is also 8, then (i) what is the atomic number of the atom and (ii) what is the charge on the atom? [/question] [solution] Solution: (i) Atomic number = number of protons.= 8. (ii) Number of electrons (-ve) = number of protons (+ve) , therefore, the charge on the atom is 0....

## How will you find the valency of chlorine, sulphur and magnesium?

[question] Question. How will you find the valency of chlorine, sulphur and magnesium? [/question] [solution] Solution: (i) Atomic number of chlorine $=17$ Thus, outermost shell has 7 electrons. It can easily complete its octet by gaining one electron. Hence, its valency = 1. (ii) Atomic number of sulphur = 16 Thus, outermost shell has 6 electrons. Hence, valency = 8 – 6 = 2 (iii) Atomic number of magnesium = 12\ Thus, outermost shell has 2 electrons. It can easily complete its octet by loosing ...

## If K and L shells of an atom are full,

[question] Question. If K and L shells of an atom are full, then what would be the total number of electrons in the atom? [question] [solution] Solution: The maximum number of electrons that can occupy K and L-shells of an atom are 2 and 8 respectively. Therefore, if K and L-shells of an atom are full, then the total number of electrons in the atom would be (2 + 8) = 10 electrons. [/solution]...

## Write the distribution of electrons in carbon and sodium atoms?

[question] Question. Write the distribution of electrons in carbon and sodium atoms? [/question] [solution] Solution: The total number of electrons in a carbon atom is 6. The distribution of electrons in carbon atom is given by: First orbit or K-shell = 2 electrons Second orbit or L-shell = 4 electrons Or, we can write the distribution of electrons in a carbon atom as 2, 4. The total number of electrons in a sodium atom is 11. The distribution of electrons in sodium atom is given by: First orbit...

## Helium atom has an atomic mass of 4 u

[question] Question. Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have? [/question] [solution] Solution: The mass of an atom is given by the sum of the masses of protons and neutrons present in the nucleus. Since helium atom has an atomic mass of 4u and it has two protons, the protons contribute 2u to atomic mass. Hence, it must contain 2 neutrons as each neutron contributes 1u to the nucleus. [/solution]...

## Name the three sub-atomic particles of an atom

[question] Question. Name the three sub-atomic particles of an atom. [/question] [solution] Solution: The three sub-atomic particles of an atom are: Protons, Electrons and Neutrons. [/solution]...

## What do you think would be the observation

[question] Question. What do you think would be the observation if the $\alpha$-particle scattering experiment is carried out using a foil of a metal other than gold? [/question] [solution] Solution: If $\alpha$-particle scattering experiment is carried out using a foil of any metal as thin as gold foil used by Rutherford, there would be no change in observations. But since other metals are not so malleable. So, such a thin foil is difficult to obtain. If we use a thick foil, then more $\alpha-$...

## On the basis of Rutherford’s model of an atom,

[question] Question. On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom? [question] [solution] Solution: Protons which are positively-charged particles are present in the nucleus of an atom. [/solution]...

## On the basis of Thomson’s model of an atom,

[question] Question. On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole. [/question] [solution] Solution: J.J. Thomson, the discoverer of the electron believed that the atom is a uniform sphere of positive charge with electron embedded in it. This model explained the electrical neutrality of atom, but it failed to explain how these fundamental particles were arranged in the atom. [/solution]...

## If an atom contains one electron

[question] Question. If an atom contains one electron and one proton, will it carry any charge or not? [/question] [solution] Solution: An electron is a negatively charged particle, where as a proton is a positively charged particle. The magnitude of their charges is equal. Therefore, it will be a neutral atom. [solution]...

## What are canal rays?

[question] Question. What are canal rays? [/question] [solution] Solution: Canal rays are beams of positive ions that are created by certain types of gas discharge tubes. They were first observed in Crookes tubes during experiments by the German scientist Eugen Goldstein, in 1886. Later work on anode rays by Wilhelm Wien and J. J. Thomson led to the development of mass spectrometry [/solution]...