Question

example 2: sodium (na)
electron configuration:
noble gas configuration (abbreviated):

Explanation:

Step1: Recall sodium's atomic number

Sodium (Na) has an atomic number of 11.

Step2: Write electron - configuration

Electrons fill orbitals in order of increasing energy. The electron - configuration is $1s^{2}2s^{2}2p^{6}3s^{1}$.

Step3: Write noble - gas configuration

The nearest noble gas to sodium with a lower atomic number is neon (Ne) which has an electron - configuration of $1s^{2}2s^{2}2p^{6}$. So the noble - gas configuration of sodium is $[Ne]3s^{1}$.

Answer:

Electron Configuration: $1s^{2}2s^{2}2p^{6}3s^{1}$
Noble Gas Configuration (abbreviated): $[Ne]3s^{1}$