Answer : The electronic configuration of argon (Ar) is, 
Explanation :
Element is, Argon (Ar)
Atomic number of argon = 18
The number of electrons = 18
As we know that the number of electrons is equal to the number of protons and the number of proton is equal to the atomic number.
Electronic configuration : It is defined as the arrangement or distribution of electron of atom in a atomic orbital.
Hence, the electronic configuration of argon is,
Answer:
A reference point.
Explanation:
Reference point:
A reference point is a point which is used to determine weather the object is in motion or not. The moving object is compared with the reference point.
An object is in the state of motion when its distance is changed relative to the other object or reference point.
In order to determine weather an object is moving or not a point of reference is needed.
Without reference point displacement can not be measured
Difference Between Empirical and Molecular Formulas. The key difference between empirical and molecular formulas is that an empirical formula only gives the simplest ratio of atoms whereas a molecular formula gives the exact number of each atom in a molecule. In chemistry, we often use symbols to identify elements and molecules.
Hope I helped :)
