Question

1. Define the following terms:

a. Family versus Period on the periodic table

b. Orbit versus orbital

c. Aufbau principle

d. Hund’s rule

e. Pauli exclusion principle

f. Emission versus Absorption Spectrum

2. What are the fundamental particles present in an atom?

3. When an isotope is named, Calcium - 41, what does the 41 mean?

4. How would you know how many protons Calcium has?

5. What is the frequency and wavelength of a photon with the energy equivalent to
1.33 x 10^-18 J?    

6. The above photon has energy in which region of the electromagnetic spectrum?

7. How many quantum numbers are needed to define the probability of finding the electron in a given region of space in the hydrogen atom? Give the names, symbols and selection rules for these quantum numbers?

Answer 1

1. Elements of nearly same properties belong to a family in aperiodic table. A family in a periodic table is presented as a vertical series and sometimes called a group. Like- Li,Na,K,Rb,Cs,Fr belongs to Alkali metals family. Where as a period contains the elements whose outer shell have the same principle quantum number and they are persented horizentally. like - Li,Be,B,C,N,O,F,Ne belongs to 2nd period as all have principle quantum value for the outer shell = 2.

2. Orbit is a two dimensional path in which an electron revolves around the nucleus.It is taken as electron's path in bohr and sommerfeld theory. However according to Hiesenberg's uncertainty principle,we can't determine the position and momentum of an electron simultaneously with arbitrary precision. In that orbital is a region in space, where the probability of finding an electron is highest.

3. According to Aufbau Principle , electrons will first go to the lowest vacant orbital,before going to any orbital of higher energy. It directs a way to write electronic configuration.

4. Hund's rule states that in case if filling orbitals with same energy, every orbitals will be first singly occupied before any orbital gets apair of electron.