Water can only evaporate when it is heated. When water is under heat, the water molecules vibrate and move around so quickly that the molecules escape into the atmosphere. The molecules become less and less dense as they float into the air.
An atom will usually form either an ionic bond or covalent bond with another atom but not both.
Ionic bonds are the kind of bonds that result when one atom transfers or gives up electrons and another atom receives them and adds them to its own energy shells.
An example is sodium metal and chlorine gas. Sodium gives up two of its electrons and Chlorine receives them and the two elements form an ionic bond to create sodium chloride, a new compound.
Covalent bonds are the kind of bonds formed when two atoms decide to share electrons. No atom gives up any electrons and neither does the other atom receive any. An example is water. An oxygen atom shares two of its electrons with two hydrogen atoms to form a molecule of water (H2O).
Earth formation and evolution giant rotating cloud of gas
Nitrogen is an essential nutrient for plant growth. But farmers who cultivate pulse crops like green gram, bengal gram,black gram, etc. do not apply nitrogenous fertilizers during cultivation because of following reason
1. Leguminous plants like green gram, bengal gram,black gram contain nitrogen fixing RHIZOBIUM bacteria which convert nitrogen gas of air into nitrogen compounds which can be used by plants for their compounds
2. The nitrogen fixing Rhizohium bacteria live in the root nodules of leguminous plants.
