- The total number of proton and neutron in nucleus is called Mass number, represented by “A”.
- An ion is formed when an atom loss or gains an electron during a chemical reaction.
- The negative ion is known as “Anion”.
- Some element has two or more different atoms, these atoms have same atomic number but different mass number is called “Isotopes”.
- The electron in the highest shell is involved in bonding and they are called valance electron.
- The combining capacity of the atoms to form molecules either with same or different elements is known as valiancy.
- It is impossible for life to sustain itself without water.
- The mass of proton is 1837 times greater than that of electron.
- “Law of Constant Composition” was given by a French chemist Joseph Proust.
- Hydrogen has three isotopes i.e. Protium, Deuterium and Tritium.