Mendeleev’s original periodic table is different from the modern periodic table - Edexcel - GCSE Chemistry - Question 5 - 2017 - Paper 1
Question 5
Mendeleev’s original periodic table is different from the modern periodic table.
(a) Give one difference between Mendeleev’s early periodic table and the modern per... show full transcript
Worked Solution & Example Answer:Mendeleev’s original periodic table is different from the modern periodic table - Edexcel - GCSE Chemistry - Question 5 - 2017 - Paper 1
Step 1
Give one difference between Mendeleev’s early periodic table and the modern periodic table.
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Answer
One difference is that Mendeleev's periodic table was arranged primarily by increasing atomic mass, whereas the modern periodic table is arranged by increasing atomic number. This means that Mendeleev sometimes placed elements in groups based on similar properties, even when their atomic mass suggested they should be in a different order.
Step 2
State the atomic number of argon.
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Answer
The atomic number of argon is 18.
Step 3
Give the symbol of another element in the same group as argon.
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Answer
The symbol of another element in the same group as argon is He (Helium).
Step 4
Which row of the table shows the correct relative charges of an electron, a neutron and a proton?
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Answer
The correct row is C, which states that an electron has a charge of -1, a neutron has a charge of 0, and a proton has a charge of +1.
