NameDate

APSMrs. Jiménez

Partners:

Lab Activity:Periodic Trends – Atomic Radius

Some properties of elements show repeating patterns on the periodic table. This is called periodicity.

One of these properties is atomic radius. Atomic radius is the distance from the nucleus of an atom to its outermost electron/orbital.

Procedure:

  1. For the following data, plot the atomic number on the x-axis and atomic radius on the y-axis. Plot each period in a different color. When connecting the dots, use a plain pencil to connect the dots between periods, but colored pencil to connect the dots WITHIN periods.
  2. Follow all graphing rules! Pull these up on your Ipad from the class website and follow each one. This is a graphing review lab!
  3. Make a key (in a box) to show the different periods (1 -4).
  4. Using your graph, predict an atomic radius for N, Al, and Sc. Fill these predictions into Table #2 below. Show your “work” for this by drawing a dotted pencil line from your graph to the y axis to indicate your extrapolated data.

Table 1 – Elemental Data

Element / Atomic Number / Atomic Radius (pm)
H / 1 / 32
He / 2 / 37
Li / 3 / 130.
Be / 4 / 99
B / 5 / 84
C / 6 / 75
N / 7 / ?
O / 8 / 64
F / 9 / 60
Ne / 10 / 62
Na / 11 / 160.
Mg / 12 / 140.
Al / 13 / ?
Si / 14 / 114
P / 15 / 109
S / 16 / 104
Cl / 17 / 100.
Ar / 18 / 101
K / 19 / 200.
Ca / 20 / 174
Sc / 21 / ?
Ti / 22 / 148
V / 23 / 144
Cr / 24 / 130
Mn / 25 / 129
Fe / 26 / 124
Co / 27 / 118
Ni / 28 / 117
Cu / 29 / 122
Zn / 30 / 120
Ga / 31 / 123
Ge / 32 / 120.
As / 33 / 120.
Se / 34 / 118
Br / 35 / 117
Kr / 36 / 116
  1. Use your I-pads to find the “NY State Reference Tables, Table S” and look up the true atomic radius of N, Al, and Sc. Fill these values in on Table #2 also in the third column for “accepted atomic radius.”

Table 2 – Predicting Atomic Radius

Element / Predicted Atomic Radius / Accepted Atomic Radius / Percent Error
N
Al
Sc
  1. Perform three percent error calculations using this equation:

Accepted value – Experimental value x 100 = percent error

Accepted value

Where the accepted value = the one you looked up and the experimental value is the one you predicted using the graph.

Show these calculations in the correct 3 step method with units and sig figs below! Then fill in your final percent error values in Table #2 above.

Calculations

  1. If time allows, try to create a replicate graph on your ipad by going to google account and then google spreadsheets. It works a LOT like MS Excel. Be sure that even though this is a computer based graph, that it also includes axes labels, units, overall title, key, etc. just like a handmade graph would. You will have to either first type in all the data!! We will do more on this after Christmas

Analysis Questions and Extra Research

  1. What is atomic radius?
  1. Look at your graph and explain what trend you see in atomic radius as you go down a group of elements.

2b. Using your Ipad to research, clearly explain WHY you see the trend in #2 above.

  1. Look at your graph and explain what trend you see in atomic radius as you go across a period.

3b. Using your Ipad to research, clearly explain WHY you see the trend in #3 above. (This one is a bit tricky! Explain it well for full credit and don’t copy and paste!)

References (Properly list all references used to determine your answers above. APA format must be used. No In-text citations are required.)