Give the number of electrons in the species 

Write the complete symbol for the atom with the given atomic number (Z) and atomic number (A).
(i) Z = 17,   A = 35 
(ii) Z = 92,  A = 233
(iii) Z = 4,   A = 9.

105. An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign the symbol to this ion. 

What is the atomic number and mass number of A³⁺ ion with 21 electrons and 25 neutrons?

Define isotopes, isobars and isotones.

Name different isotopes of hydrogen. Give their atomic numbers and mass numbers.

Isotopes of an element have similar chemical properties and isobars have different chemical properties. Explain.