use the periodic to fill in the numbers in the electron configurations shown below. b: 1s² 2sᴬ2pᴮ a = b = done

Explanation:

Step1: Identify the element

Boron (B) has an atomic number of 5.

Step2: Determine electron - filling rules

Electrons fill orbitals in the order of increasing energy: 1s, 2s, 2p. The 1s orbital can hold 2 electrons, the 2s orbital can hold 2 electrons, and the 2p orbital can hold 6 electrons.

Step3: Calculate the number of electrons in 2s and 2p for boron

For boron with 5 electrons, 2 electrons go in the 1s orbital. Then, 2 electrons go in the 2s orbital and 1 electron goes in the 2p orbital. So for the electron - configuration $1s^{2}2s^{A}2p^{B}$, $A = 2$ and $B = 1$.

Answer:

A = 2 B = 1