Question

1. which element has the ground state electronic configuration, 1s22s22p63s23p64s1? bromine phosphorus potassium calcium

Explanation:

Step1: Count electrons in configuration

The electron - configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}$ has a total of $2 + 2+6 + 2+6 + 1=19$ electrons.

Step2: Match with atomic number

The atomic number of an element is equal to the number of electrons in its neutral state. The element with atomic number 19 is potassium (K).

Answer:

potassium