Question

How many lines of atoms would you expect to see on the collector plate of a Stern-Gerlach apparatus if the experiment is done with
(a) lithium and

(b) beryllium? Explain.

Short answer

(a) Two lines of the atom is lithium.

(b) One line of atoms is beryllium.

Step-by-step solution

Part (a) step 1: Given Information

We need to find how many lines of lithium

Part (a) step 2: Explanation

Now, we know that the lithium atom has three electrons .So, lithium atoms should behave hydrogen atoms. Lithium atoms could exist in the two following states:

$\left(2,0,0,-\frac{1}{2}\right)and\left(2,0,0,+\frac{1}{2}\right)$

Then, two lines of atom is lithium.

Part (b) step 2: Given Information

We need to find how many lines of beryllium.

Part (b) step 2: Explanation

At last, we know that the beryllium atom has four electrons. The electrons in both $1s$and$2s$ states are filled. Because the two-electron magnetic moments point in opposite directions beryllium has no net magnetic moment.

Therefore, one line of atoms is beryllium.