Question

We have learnt about the periodic table in Chemistry. Choose an element and find out its atomic number and mass number using the periodic table. Calculate the number of protons, neutrons and electrons in the element and build its 3D atomic model using ping pong balls or craft balls. Using this model,

1. learn the concept of atomic and nuclear structure
2. predict the change in the element on subtraction or addition of a proton, electron or neutron
3. understand the concept of isotopes, isobars and isotones

Answer 1

Chosen Element: Carbon (C)

Carbon has atomic number 6 and mass number 12.

Protons = 6

Electrons = 6

Neutrons = 12 − 6 = 6

Using 6 ping-pong balls for protons, 6 for neutrons and 6 for electrons, a 3D model of the carbon atom can be prepared.

(i) Atomic and Nuclear Structure

The nucleus contains 6 protons and 6 neutrons, while 6 electrons revolve around the nucleus.

(ii) Change in the Element

• Addition/removal of a proton changes the element.
• Addition/removal of an electron forms an ion but does not change the element.
• Addition/removal of a neutron forms a different isotope of the same element.

(iii) Isotopes, Isobars and Isotones

• Isotopes: Same atomic number, different mass numbers.
  Example: ¹²C and ¹⁴C
• Isobars: Same mass number, different atomic numbers.
  Example: ¹⁴C and ¹⁴N
• Isotones: Same number of neutrons, different atomic numbers.
  Example: ¹⁴C and ¹⁵N (both have 8 neutrons).