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The positions of five elements, A, B, C, D and E, are shown in the periodic table - Edexcel - GCSE Chemistry - Question 5 - 2012 - Paper 1
Question 5
The positions of five elements, A, B, C, D and E, are shown in the periodic table. These letters are not the atomic symbols of these elements. (a) Which element, A,... show full transcript
Worked Solution & Example Answer:The positions of five elements, A, B, C, D and E, are shown in the periodic table - Edexcel - GCSE Chemistry - Question 5 - 2012 - Paper 1
Step 1
Step 2
Step 3
Explain how Mendeleev was able to predict the properties of element D.
Answer
Mendeleev predicted the properties of element D by recognizing patterns in the properties of elements in the same group. He left spaces for undiscovered elements in his periodic table based on the trends he observed, allowing him to estimate the properties of these unknown elements.
Step 4
Explain how you can use this information to calculate the number of protons in an atom of element D.
Answer
Since element C contains 29 protons, and D is situated two places further in the periodic table, we expect element D to have 31 protons. This is because elements are arranged by increasing atomic number, which corresponds to the number of protons.
Step 5
Describe the numbers and positions of electrons, protons and neutrons in this atom.
Answer
In an atom with an atomic number of 9, there are 9 protons located in the nucleus. The number of neutrons can be calculated by subtracting the atomic number from the mass number: 19 (mass number) - 9 (atomic number) = 10 neutrons. Therefore, there are 10 neutrons also in the nucleus. The electrons, which are negatively charged, are arranged in energy levels around the nucleus; specifically, there will be 9 electrons positioned in the electron shells according to the Aufbau principle.