Question

Principal quantum number determines

1. the size of the electron orbital.
2. the shape of the electron orbital
3. the orientation of the electron orbital
4. the direction of electron spin

Answer 1

Correct Answer - Option 1 : the size of the electron orbital.

The correct answer is the size of the electron orbital.

CONCEPT:

• Atomic orbitals are the regions where there is a maximum probability of finding electrons.
• An atom can have a large number of atomic orbitals.
• Atomic orbitals are distinguished using quantum numbers-  principal quantum number(n), azimuthal quantum number(l), magnetic quantum number(ml) and soin quantum number(ms)
• Azimuthal quantum number(l) is also known as orbital angular momentum quantum number.
• It defines the 3-dimensional shape of an orbital.
• Magnetic quantum number(m_s): It gives information about the spatial orientation of the orbital with respect to a standard set of coordinate axis.
• The value ranges from –l to +l
• Spin quantum number(m_s) refers to the orientation of spin of the electron.
• Values - +1/2 or -1/2.

EXPLANATION:

• Principal quantum number n determines the size of the atomic orbital.
• It is a positive integer with values n= 1,2,3,….
• It also identifies the shell.
• The number of allowed orbitals is given by n²
•  All the orbitals of a given value of ‘n’ constitute a single shell of the atom.

• n	1	2	3
  Shell	K	L	M

   

• Size of the orbital increases with an increase in principal quantum number.