Q7 of 24 Page 165

_________ have equal number of neutrons.

i) Isobars ii) Isotones


iii) Isotopes iv) Mass Numbers

isotones

These are the atoms of different elements with same number of neutrons. Example : 6C13 and 7N14


Number of neutrons is obtained by subtracting atomic number from atomic mass number.


Number of neutrons in 6C13 is (13-6) 7.


Number of neutrons in 7N14 is (14-7) 7.


● Isobars are the atoms of different elements having same mass number but different atomic numbers.


● Isotopes are the atoms of same element with same atomic number but


different mass number.


● Mass numbers is the sum of protons and neutrons.

More from this chapter

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5

Calculate the gram molecular mass of water from the values of gram atomic mass of Hydrogen and of Oxygen.

Gram atomic mass of Hydrogen = 1 g


Gram atomic mass of Oxygen = 16 g

 6

One mole of any substance contains 6.023 x 1023particles.

If 3.0115 x 1023 particles are present in CO2, find the number of moles.

 8

Classify the following based on atomicity:

i) Chlorine ii) Neon


iii) Phosphorous iv) Ozone

 9

Identify and correct the mistake in each of the following:

i) The molar volume of gas at STP is 22.4 cm3.


ii) 2 x R.M.M. = V.D.


iii) An atom cannot exist independently.


iv) The ratio of atoms in a molecule may be integral or simple or may not be fixed.


v) H2O is a homo atomic molecule.