Define mass number of an element.

The mass number of an element is 18. It contains 7 electrons. What is the number of protons and neutrons in it ? What is the atomic number of the element ?

The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it ? What is the atomic number of the element ?

Define atomic mass of an element.

Define an element.

Define atomic number.

General instructions same as in chapter 1. Assertion:Rydberg's constant varies with mass number of a given element. Resaon:The reduced mass of the electron is dependent on a given element.

If A and B be two sets containing 6 and 3 elements respectively, what can be the minimum number of elements in AuuB ? Also, find the maximum number of elements in AuuB .

Define valency of an element.

Define valency of an element