Maharashtra Board Solutions for Chapter: Inside the Atom, Exercise 6: Use your brain power

The symbol used for oxygen is ‘$\mathrm{O}$’. There are $8$ protons and $8$ neutrons in its nucleus. From this determine the atomic number (Z) and mass number (A) of oxygen and arrange these in a conventional symbol. 

Atomic number of carbon is $6$. How many electrons are there in a carbon atom? 

A sodium atom contains $11$ electrons. What is the atomic number of sodium? 

The atomic number and mass number of magnesium are $12$ and $24$ respectively. How will you show this by the convention symbol? 

The atomic number and mass number of calcium are $20$ and $40$ respectively. Deduce the number of neutrons present in the calcium nucleus.