Practice Questions

Give the symbols of a set of isotopes.

Give the symbols of a set of isobars.

Write the electronic configuration of an element whose atomic number is 12.

Calculate the charge by mass ratio for ${\mathrm{He}}^{+} \mathrm{and} {\mathrm{He}}^{2+}$ in comparison to that of an electron.

Isotopes find important applications in a variety of areas in the fields of medicine, agriculture, generation of cheaper electricity, industry, radiocarbon dating, etc.
Which isotope is used for finding the age of a fossil?

Nucleus is positively charged whereas electrons are negatively charged but Niels Bohr proved that electrons never fall into the nucleus. Atom is always stable.
What lesson do you learn from this example for your day-to-day life?
 

The journey from Dalton's model of atom to Thomson's model of atom to Rutherford's model of atom to Bohr's model of atom is a long and strenuous one. Each model has its merits and drawbacks. Even Bohr's model of atom is not the final answer to the structure of atom.
Give distinguishing features between Thomson's model and Rutherford's model of atom.

The journey from Dalton's model of atom to Thomson's model of atom to Rutherford's model of atom to Bohr's model of atom is a long and strenuous one. Each model has its merits and drawbacks. Even Bohr's model of atom is not the final answer to the structure of atom.
State a defect of Bohr's model of atom.