Atoms and Molecules Numericals

An element has an atomic number of 11 and its mass number is 23. What is the arrangement of electrons in the shells? State nuclear composition of an atom of the element.

What is the number of molecules in 1.5 moles of ammonia ?

If the number of electrons in an ion Z3– is 10, the atomic number of element Z will be :

The number of electrons in an ion Y2+ is 10. The atomic number of element Y is most likely to be :

The atom of an element X contains 17 protons, 17 electrons and 18 neutrons whereas the atom of an element Y contains 11 protons, 11 electrons and 12 neutrons.

1. What type of ion will be formed by an atom of element X ? Write the symbol of ion formed.
2. What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from X ?
3. What type of ion will be formed by an atom of element Y ? Write the symbol of ion formed.
4. What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from Y ?
5. What is the atomic mass of (i) X, and (ii) Y ?
6. What could the elements X and Y be ?

What is the numerical value of Avogadro number ?

What name is given to the number 6.022 × 1023 ?

What name is given to this number ?