Student Exploration: Periodic Trends

Vocabulary: atomic radius, electron affinity, electron cloud, energy level, group, ion, ionization

energy, metal, nonmetal, nucleus, period, periodic trends, picometer, valence electron

Prior Knowledge Questions (Do these BEFORE using

the Gizmo.)

1. On the image at right, the two magnets are the same.

Which paper clip would be harder to remove? Magnet

A

2. Which magnet would be most likely to attract additional paper clips? B

3. What is the relationship between the thickness of the book and the ability of the magnet to

hold on to and attract paper clips? The thicker the metal, the harder it is for the

 magnet to attract more paper clips.

Gizmo Warm-up

Just as the thickness of a book changes how strongly a magnet attracts a

paper clip, the size of an atom determines how strongly the nucleus

attracts electrons. In the Periodic Trends Gizmo, you will explore this

relationship and how it affects the properties of different elements.

The atomic radius is a measure of the size of the electron cloud, or the region where

electrons can be found. To begin, check that H (hydrogen) is selected in Group 1 on the left.

Turn on Show ruler. To measure the radius, drag one end of the ruler to the proton in the

nucleus and the other end to the electron. Click Save radius to record the value.

1. What is the radius of hydrogen? 53pm.

Notice that the radius is measured in picometers (pm). A picometer is one trillionth of a

meter.