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In 1869, Dmitri Mendeleev produced his periodic table of the elements - AQA - GCSE Chemistry - Question 3 - 2014 - Paper 3
Question 3
In 1869, Dmitri Mendeleev produced his periodic table of the elements. Mendeleev placed the alkali metals in the same group. 3 (a) What evidence did Mendeleev use ... show full transcript
Worked Solution & Example Answer:In 1869, Dmitri Mendeleev produced his periodic table of the elements - AQA - GCSE Chemistry - Question 3 - 2014 - Paper 3
Step 1
What evidence did Mendeleev use to decide that the alkali metals should be in the same group?
Answer
Mendeleev placed the alkali metals in the same group due to their similar properties, particularly their reactivity with water and their formation of hydroxides. For example, sodium and potassium both produce alkaline solutions when reacting with water, demonstrating their close relationship.
Step 2
Step 3
Step 4
State two properties of transition elements that make them more useful than alkali metals for making water pipes.
Answer
Transition elements are typically stronger and more resistant to corrosion than alkali metals. This makes them more suitable for use in water pipes, as they can withstand higher pressures and last longer without degrading.
Step 5
Describe and explain the trend in reactivity of the alkali metals (Group 1).
Answer
The reactivity of alkali metals increases down the group. This trend occurs because the outer electron is further from the nucleus and experiences greater shielding from inner electrons. Consequently, the outer electron is lost more easily, leading to increased reactivity as you move from lithium to cesium.