Question 6 – The periodic table - Questions

Gallium had not yet been discovered when Dmitri Mendeleev published his periodic table in 1869.

Table 1 displays a comparison between the properties Mendeleev predicted for this missing element (which he termed eka-aluminium) and the physical and chemical properties of gallium determined after its discovery in 1875.

Table 1

Property	Predicted property (eka-aluminium)	Actual property (gallium)
Relative atomic mass	68	69.7
Density in $g/cm3\text{g/cm}^3$	5.9	5.91
Formula of oxide	$Ea2O3\text{Ea}_2\text{O}_3$	$Ga2O3\text{Ga}_2\text{O}_3$
Melting point	Low	$\ ^\circ\text{C}$

Describe how Mendeleev was able to make such accurate predictions for the properties of gallium before it was discovered.

Gallium had not yet been discovered when Dmitri Mendeleev published his periodic table in 1869.

Table 1

Property	Predicted property (eka-aluminium)	Actual property (gallium)
Relative atomic mass	68	69.7
Density in $g/cm3\text{g/cm}^3$	5.9	5.91
Formula of oxide	$Ea2O3\text{Ea}_2\text{O}_3$	$Ga2O3\text{Ga}_2\text{O}_3$
Melting point	Low	$\ ^\circ\text{C}$

Describe how Mendeleev was able to make such accurate predictions for the properties of gallium before it was discovered.

The periodic table

Question 2

Table 1

The periodic table

Question 2

Table 1

The periodic table

Question 2

Table 1

The periodic table Questions

The periodic table

Question 2

Table 1

The periodic table Questions