if an element has the atomic number 20, what sublevels are present? it has a p sublevel. it has an s…

if an element has the atomic number 20, what sublevels are present? it has a p sublevel. it has an s sublevel. the first energy level has an s; the second energy level has an s and a p; the third energy level has an s, p, and d; the fourth energy level has an s. the first energy level has an s; the second and third energy levels have an s and a p; the fourth energy level has an s.

if an element has the atomic number 20, what sublevels are present? it has a p sublevel. it has an s sublevel. the first energy level has an s; the second energy level has an s and a p; the third energy level has an s, p, and d; the fourth energy level has an s. the first energy level has an s; the second and third energy levels have an s and a p; the fourth energy level has an s.

Answer

Explanation:

Step1: Recall electron - filling rules

Electrons fill energy levels and sublevels according to the Aufbau principle, Pauli - exclusion principle, and Hund's rule. The order of filling is (1s<2s < 2p<3s<3p<4s<3d) etc.

Step2: Determine electron number

An element with atomic number 20 has 20 electrons.

Step3: Fill electrons into sublevels

The first energy level ((n = 1)) has only an (s) sublevel and can hold 2 electrons ((1s^{2})). The second energy level ((n=2)) has an (s) and a (p) sublevel, with (2s^{2}2p^{6}) (2 in (s) and 6 in (p)). The third energy level ((n = 3)) has an (s), (p), and (d) sublevel, filled as (3s^{2}3p^{6}) (before filling (3d), (4s) is filled first according to the Aufbau principle). The fourth energy level ((n=4)) starts to be filled, and since we have 20 electrons in total, after filling the above sublevels ((2 + 2+6+2 + 6)), the remaining 2 electrons go into (4s), giving the electron - configuration (1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}).

Answer:

The first energy level has an s; the second and third energy levels have an s and a p; the fourth energy level has an s.