How does a 2s orbital differ from a 1s orbital?

The 2s and 1s orbitals are both types of s orbitals, which are spherical in shape. However, they differ in several ways:

1. Principal Quantum Number: The principal quantum number (n) for a 1s orbital is 1, while for a 2s orbital, it is 2. This number indicates the main energy level of the electron in the orbital.

2. Energy: The 2s orbital has a higher energy level than the 1s orbital. This is because the principal quantum number is higher for the 2s orbital.

3. Size and Distance from the Nucleus: The 2s orbital is larger and the electron in a 2s orbital is located further from the nucleus compared to a 1s orbital. This is due to the increase in the principal quantum number.

4. Number of Nodes: Nodes are regions where there is zero probability of finding an electron. A 1s orbital has no nodes, while a 2s orbital has one node. This means there is a region in the 2s orbital where there is zero probability of finding an electron.

5. Electron Capacity: Both the 1s and 2s orbitals can hold a maximum of two electrons. However, the electrons in the 2s orbital have a higher energy than those in the 1s orbital.

In summary, while both are types of s orbitals and can hold the same number of electrons, the 2s orbital is at a higher energy level, is larger, is further from the nucleus, and has one node, unlike the 1s orbital.