Answer:
Li atoms readily give up one electron to form positively charged, Li+ ions. These ions have the same stable electron configuration as the noble gas helium. All Group 1 atoms can lose one electron to form positively charged ions.
Explanation:
A physical property is any property that is measurable, whose value describes a state of a physical system. The changes in the physical properties of a system can be used to describe its changes between momentary states. Physical properties are often referred to as observables. They are not modal properties.
The first bond between two atoms is always a sigma bond and the other bonds are always pi bonds and a hybridized orbital cannot be involved in a pi bond. Thus we need to leave one electron (in case of Carbon double bond) to let the Carbon have the second bond as a pi bond.
Explanation:
A chemical reaction is defined as the reaction in which bonds between the reactants either break or form which leads to the formation of a new substance.
For example, 
So, when we drop a sodium metal into water then it produces a frizzing sound which shows the metal is reacting with water.
We know that when two aqueous solutions chemically react with each other then it may lead to the formation of an insoluble substance which is known as precipitate.
This means that formation of a precipitate is also a chemical reaction.
Thus, we can conclude that following are the statements which show evidence for a chemical reaction.
- Dropping sodium metal into water produces fizzing.
- Mixing two aqueous solutions produces a precipitate.