Question

What is the neutral atom that has its first two energy levels filled, has 8 electrons in its third energy level, and has no other electrons? Enter the name of the element, not the abbreviation.

Answer 1

Argon

Ar 1s²2s²2p⁶3s²3p⁶

Answer 2

Answer:

Argon

Explanation:

The arrangement of electrons in an atom is governed by the Aufbau principle according to which electrons are added to atomic orbitals such that the lowest energy orbitals get occupied first before the higher energy orbitals. The arrangement of energy levels in increasing energy order is:

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p......

's' , 'p', 'd' orbitals can accommodate a maximum of 2,6 and 10 electrons respectively.

From the given information:

First energy level corresponds to n = 1, and is fully filled i.e. 1s²

Second energy level corresponds to n = 2, and is fully filled i.e. 2s²2p⁶

Third energy level corresponds to n = 3 and it has 8 electrons i.e. 3s²3p⁶

The neutral atom has a total of 18 electrons with an electronic configuration of:

1s²2s²2p⁶3s²3p⁶

Based on the periodic table the atom is with atomic number = 18 is argon (Ar)