Question

periodic trends: straw lab
objective: to create a visual representation of the following periodic trends: atomic size, ionization energy and electronegativity.
atomic radius: the size of an atom measured in either nanometers (nm) or angstroms (å).
ionization energy: the energy needed to remove an electron from an atom measured in kilojoules per mole (kj/mol) of an atom.
electronegativity: the relative ability of an atom to attract electrons towards itself.
materials: for this lab you will need a sheet with 3 small periodic tables, straws, scissors, a metric ruler, your notebook and access to a hot glue gun.
procedure:

1. draw and complete the data table for each trend in your lab notebook. each person should have their own data tables in their own notebooks!
2. for each trend, calculate the scale factor according to the instructions. using the scale factor, measure the straw and cut it to the appropriate size.
3. you will then use the glue gun to glue the straw to the periodic table in the box that represents the element’s location on the periodic table.
4. answer the questions for each trend in your lab notebook. everyone should have their own answers in their own notebook!

atomic radius:
the radius of the following atoms has been estimated to have the following values:

name	symbol	atomic number	size of radius (nm)	calculated straw length (cm)
chlorine	cl	17	0.0999
bromine	br	85	0.114
iodine	i	53	0.1133
sodium	na	11	0.186
magnesium	mg	12	0.160

Explanation:

To calculate the "Calculated Straw Length (cm)" for each element, we need to determine the scale factor. Let's assume the scale factor is to convert nanometers (nm) to centimeters (cm) and then apply a multiplier (for example, if we want to scale up the radius to a visible straw length, let's say we use a scale factor of 1000, meaning 1 nm = 1000 cm in the model, but we need to check the lab instructions. However, typically, to convert nm to cm, we know that 1 nm = \(10^{-7}\) cm, but for a lab model, we might use a different scale. Wait, maybe the scale factor is to multiply the atomic radius (in nm) by 100 to get cm (since 1 nm = \(10^{-7}\) cm is too small, so maybe the lab uses a different scale, like 1 nm = 1 cm for the model? Wait, no, that can't be. Wait, maybe the scale factor is to take the atomic radius (in nm) and multiply by 100 to get mm, then convert to cm? Wait, let's re - examine.

Wait, the atomic radius is in nanometers. Let's say we want to represent the atomic radius as a straw length in centimeters. Let's assume the scale factor is 100 (so 1 nm = 0.01 cm? No, that would make the straws too short. Wait, maybe the scale factor is 1000, so 1 nm = 0.001 mm? No, this is confusing. Wait, maybe the lab has a specific scale factor. Let's suppose that the scale factor is to multiply the atomic radius (in nm) by 100 to get cm. Let's test with Fluorine:

Step 1: For Fluorine

Atomic radius = 0.064 nm. If we use a scale factor of 100 (to convert nm to cm, assuming 1 nm = 0.01 cm? No, 1 nm = \(10^{-7}\) cm. Wait, maybe the lab is using a different approach. Wait, maybe the scale factor is to take the atomic radius (in nm) and multiply by 10 to get mm, then divide by 10 to get cm? No. Wait, perhaps the scale factor is 100, so:

Calculated Straw Length (cm)= Atomic Radius (nm)×100

For Fluorine:

Step 1: Calculate for Fluorine

Atomic Radius = 0.064 nm
Calculated Straw Length = \(0.064\times100 = 6.4\) cm

Step 2: Calculate for Chlorine

Atomic Radius = 0.0999 nm
Calculated Straw Length = \(0.0999\times100=9.99\) cm

Step 3: Calculate for Bromine

Atomic Radius = 0.114 nm
Calculated Straw Length = \(0.114\times100 = 11.4\) cm

Step 4: Calculate for Iodine

Atomic Radius = 0.1133 nm
Calculated Straw Length = \(0.1133\times100=11.33\) cm

Step 5: Calculate for Sodium

Atomic Radius = 0.186 nm
Calculated Straw Length = \(0.186\times100 = 18.6\) cm

Step 6: Calculate for Magnesium

Atomic Radius = 0.160 nm
Calculated Straw Length = \(0.160\times100=16.0\) cm

If we assume the scale factor is 100 (to make the straw lengths visible), the calculated straw lengths are:

• Fluorine: 6.4 cm
• Chlorine: 9.99 cm
• Bromine: 11.4 cm
• Iodine: 11.33 cm
• Sodium: 18.6 cm
• Magnesium: 16.0 cm

(Note: The actual scale factor should be provided in the lab instructions. If the scale factor is different, the calculations will change accordingly. For example, if the scale factor is 500, we would multiply the atomic radius by 500 instead of 100.)

Answer:

To calculate the "Calculated Straw Length (cm)" for each element, we need to determine the scale factor. Let's assume the scale factor is to convert nanometers (nm) to centimeters (cm) and then apply a multiplier (for example, if we want to scale up the radius to a visible straw length, let's say we use a scale factor of 1000, meaning 1 nm = 1000 cm in the model, but we need to check the lab instructions. However, typically, to convert nm to cm, we know that 1 nm = \(10^{-7}\) cm, but for a lab model, we might use a different scale. Wait, maybe the scale factor is to multiply the atomic radius (in nm) by 100 to get cm (since 1 nm = \(10^{-7}\) cm is too small, so maybe the lab uses a different scale, like 1 nm = 1 cm for the model? Wait, no, that can't be. Wait, maybe the scale factor is to take the atomic radius (in nm) and multiply by 100 to get mm, then convert to cm? Wait, let's re - examine.

Wait, the atomic radius is in nanometers. Let's say we want to represent the atomic radius as a straw length in centimeters. Let's assume the scale factor is 100 (so 1 nm = 0.01 cm? No, that would make the straws too short. Wait, maybe the scale factor is 1000, so 1 nm = 0.001 mm? No, this is confusing. Wait, maybe the lab has a specific scale factor. Let's suppose that the scale factor is to multiply the atomic radius (in nm) by 100 to get cm. Let's test with Fluorine:

Step 1: For Fluorine

Atomic radius = 0.064 nm. If we use a scale factor of 100 (to convert nm to cm, assuming 1 nm = 0.01 cm? No, 1 nm = \(10^{-7}\) cm. Wait, maybe the lab is using a different approach. Wait, maybe the scale factor is to take the atomic radius (in nm) and multiply by 10 to get mm, then divide by 10 to get cm? No. Wait, perhaps the scale factor is 100, so:

Calculated Straw Length (cm)= Atomic Radius (nm)×100

For Fluorine:

Step 1: Calculate for Fluorine

Atomic Radius = 0.064 nm
Calculated Straw Length = \(0.064\times100 = 6.4\) cm

Step 2: Calculate for Chlorine

Atomic Radius = 0.0999 nm
Calculated Straw Length = \(0.0999\times100=9.99\) cm

Step 3: Calculate for Bromine

Atomic Radius = 0.114 nm
Calculated Straw Length = \(0.114\times100 = 11.4\) cm

Step 4: Calculate for Iodine

Atomic Radius = 0.1133 nm
Calculated Straw Length = \(0.1133\times100=11.33\) cm

Step 5: Calculate for Sodium

Atomic Radius = 0.186 nm
Calculated Straw Length = \(0.186\times100 = 18.6\) cm

Step 6: Calculate for Magnesium

Atomic Radius = 0.160 nm
Calculated Straw Length = \(0.160\times100=16.0\) cm

If we assume the scale factor is 100 (to make the straw lengths visible), the calculated straw lengths are:

• Fluorine: 6.4 cm
• Chlorine: 9.99 cm
• Bromine: 11.4 cm
• Iodine: 11.33 cm
• Sodium: 18.6 cm
• Magnesium: 16.0 cm

(Note: The actual scale factor should be provided in the lab instructions. If the scale factor is different, the calculations will change accordingly. For example, if the scale factor is 500, we would multiply the atomic radius by 500 instead of 100.)