Question

3 multiple choice 5 points what is the last orbital filled by li? 2s 3s 2p 1s

Explanation:

Lithium (Li) has an atomic number of 3. Its electron configuration is \(1s^{2}2s^{1}\). Electrons fill orbitals in order of increasing energy (Aufbau principle). The \(1s\) orbital is filled first (holds 2 electrons), and then the \(2s\) orbital (holds 1 electron for Li). The \(2p\) and \(3s\) orbitals have higher energy than \(2s\) for Li and are not filled in the ground - state electron configuration of Li.

Answer:

2s