Question

1. investigate: select h. in the gizmo, the hydrogen atom is shown next to a positive charge. as you move the atom to the right, the force of attraction between the positive charge and the valence electron will increase until the electron is removed. slowly drag the atom towards the charge. after the electron is removed, use the ruler to measure the distance between the original and the final position of the electron. record the distance and ionization energy in the table, then repeat for the other group 1 elements.
2. analyze: what trend do you notice?

element distance (no units) ionization energy (kj/mol)
h
li
na
k
rb
cs
fr

Explanation:

Step1: Recall ionization - energy trend

Ionization energy is the energy required to remove an electron from an atom. For Group 1 elements (alkali - metals: H, Li, Na, K, Rb, Cs, Fr), as we move down the group, the atomic size increases.

Step2: Analyze the effect of atomic - size on ionization energy

As the atomic size increases, the outermost electron is farther from the nucleus. The effective nuclear charge on the outermost electron decreases. So, it becomes easier to remove the outermost electron.

Step3: Determine the trend

The ionization energy decreases as we move down Group 1 from H to Fr.

Answer:

The ionization energy decreases as we move down Group 1 from hydrogen (H) to francium (Fr).