1Cut All the Cards Out

Instructions

1Cut all the cards out.

2Arrange the cards in an order of your choice – but make sure you have good reasons for how you do this.

3Compare your method of sorting with another group.

This document may have been altered from the original.

Instructions

1Cut the cards out.

2Arrange them into three columns in an order of your choice, but make sure you have good reasons for how you do this.

Bromine
Atomic mass = 80
Non-metal
Liquid
Red-brown / Strontium
Atomic mass = 88
Metal
Solid
Sinks in water / Potassium
Atomic mass = 39
Metal
Solid
Floats on water
Calcium
Atomic mass = 40
Metal
Solid
Sinks in water / Sodium
Atomic mass = 23
Metal
Solid
Floats on water / Chlorine
Atomic mass = 35.5
Non-metal
Gas
Yellow-green
Lithium
Atomic mass = 7
Metal
Solid
Floats on water / Fluorine
Atomic mass = 19
Non-metal
Gas
Pale yellow / Magnesium
Atomic mass = 24
Metal
Solid
Sinks in water
Iodine
Atomic mass = 127
Non-metal
Solid
Purple-black

This document may have been altered from the original.

1Look at the properties of the top and bottom elements in each column.

2Predict the properties of the middle element and write them in.

3Compare your predictions with other students or with the actual properties.

Column A / Column B / Column C
Lithium
Atomic mass = 7
Metal
Density = 0.53g/cm3
Melting point =180°C
Boiling point = 1342°C
Reacts quickly with water / Silicon
Atomic mass = 28
Non-metal
Density = 2.3g/cm3
Melting point = 1414°C
Boiling point = 3265°C
Density of oxide = 2.63g/cm3 / Chlorine
Atomic mass = 35.5
Non-metal
Density = 0.003g/cm3
Melting point = –101°C
Boiling point = –29°C
Pale yellow-green gas
Sodium
Atomic mass = ______
______
Density = ______
Melting point = ______
Boiling point = ______
______/ Germanium
Atomic mass = ______
______
Density = ______
Melting point = ______
Boiling point = ______
Density of oxide = ______/ Bromine
Atomic mass = ______
______
Density = ______
Melting point = ______
Boiling point = ______
______
Potassium
Atomic mass = 39
Metal
Density = 0.89g/cm3
Melting point = 63°C
Boiling point = 759°C
Reacts violently with water / Tin
Atomic mass = 119
Metal
Density = 7.4g/cm3
Melting point = 232°C
Boiling point = 2602°C
Density of oxide = 6.95g/cm3 / Iodine
Atomic mass = 127
Non-metal
Density = 4.9g/cm3
Melting point = 114°C
Boiling point = 184°C
Purple-black solid

4Find these nine elements in a modern periodic table. What do you notice?

This document may have been altered from the original.

Eka-silicon

In 1871, Mendeleev published predictions for elements that he believed had yet to be discovered. One of these elements was ‘eka-silicon’. He expected that its properties would place it between silicon and tin in the same group. This table shows some of the properties of silicon and tin.

Element / Atomic mass / Density in g/cm3 / Density of its chloride in g/cm3 / Boiling point of its chloride in °C
silicon / 28 / 2.3 / 1.48 / 58
eka-silicon
tin / 119 / 7.4 / 2.22 / 114

1Calculate the mean value for each property, and write it in the table as a prediction for eka-silicon.

The table below shows Mendeleev’s predictions for eka-silicon.

Element / Atomic mass / Density in g/cm3 / Density of its chloride in g/cm3 / Boiling point of its chloride in °C
eka-silicon / 72 / 5.5 / 1.9 / 100

2Compare your answers to question 1 to Mendeleev’s predictions. Were Mendeleev’s predictions simply mean values? Explain your answer.

______

The table below shows some properties of germanium, discovered in 1886 by Clemens Winkler.

This was the predicted ‘eka-silicon’.

Element / Atomic mass / Density in g/cm3 / Density of its chloride in g/cm3 / Boiling point of its chloride in °C
germanium / 73 / 5.3 / 1.88 / 86

3Describe how close Mendeleev’s predictions were for each property.

______

4When germanium was first discovered, Winkler thought it was ‘eka-stibium’, another predicted element. Mendeleev thought it could be yet another predicted element, ‘eka-cadmium’. After Winkler purified more of the new element, he was able to provide more accurate values for its properties.

aWhat does the initial confusion suggest about Mendeleev’s confidence in his predictions?

______

bDescribe the importance of accurate results in supporting Mendeleev’s table.

______

This document may have been altered from the original.

Group 2

This table shows the boiling points of the Group 2 elements.

Element / Atomic mass / Boiling point in °C
beryllium / 9 / 2469
magnesium / 24 / 1091
calcium / 40 / 1484
strontium / 88 / 1382
barium / 137 / 1897
radium / 226 / 1737

1Plot a graph to show the change in the boiling points of Group 2 elements:

the horizontal axis is the atomic mass
the vertical axis is the temperature in °C and should go from 1000 to 2500.

2Does there appear to be a trend or pattern?

3Predict the boiling point of:

amagnesium, based only on the boiling points of beryllium and calcium

bbarium, based only on the boiling points of strontium and radium.

4Use your answers to questions 2 and 3 to identify problems when using information about existing elements to make predictions about the properties of elements yet to be discovered.

Extra challenge

The table below shows some properties of Group 7 elements.

Element / Atomic mass / Melting point in °C / Boiling point in °C
fluorine / 19 / −220 / −188
chlorine / 35.5
bromine / 80 / −7 / 59
iodine / 127 / 114 / 184

5Plot a graph to show the change in melting points and boiling points:

the horizontal axis is the atomic mass
the vertical axis is the temperature in °C and should go from −240 to 200
plot the melting point data and the boiling point data on the same graph
draw two curves of best fit and label each.

6Use your graph to estimate the melting point and boiling point of chlorine.

7Use the table and your graph to identify the state of each element at 20 °C.

This document may have been altered from the original.