Question

1. analyze: electrons are arranged in orbits called energy levels. the gizmo shows all of the first two energy levels but only part of the third energy level.

a. how many electrons can fit in the first energy level?
b. how many electrons can fit in the second energy level?
c. how many electrons fit in the part of the third energy level shown?

1. observe: click reset ( 2 ). the electrons in the outermost orbit, called valence electrons, help to create chemical bonds. create a lithium atom (3 protons, 4 neutrons, 3 electrons).

how many valence electrons are in a neutral lithium atom?

Explanation:

Step1: Recall electron - capacity rule for first level

The first energy level can hold a maximum of 2 electrons.

Step2: Recall electron - capacity rule for second level

The second energy level can hold a maximum of 8 electrons.

Step3: Consider partial third - level shown

The part of the third energy level shown usually has 8 electrons (in the s and p sub - shells).

Step4: Determine valence electrons in lithium

Lithium has 3 electrons. The first energy level takes 2 electrons, and the remaining 1 electron is in the second energy level. So, a neutral lithium atom has 1 valence electron.

Answer:

A. 2
B. 8
C. 8
D. 1