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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
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Step 3
Explain how Mendeleev was able to predict the properties of element D.
Answer
Mendeleev predicted the properties of element D by analyzing the trends and patterns of known elements in the periodic table. He noted the periodic properties based on atomic mass and left gaps for undiscovered elements, predicting that these elements would have properties similar to those of elements above and below them in the same group.
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 has 29 protons and is positioned such that element D follows it in a period, it can be inferred that element D has more protons, specifically 31 protons, as each successive element has one more proton than the previous.
Step 5
Describe the numbers and positions of electrons, protons and neutrons in this atom.
Answer
An atom with an atomic number of 9 has 9 protons located in its nucleus. The number of neutrons can be found by subtracting the atomic number from the mass number: 19 - 9 = 10 neutrons, also in the nucleus. There are 9 electrons, which are arranged in energy levels around the nucleus. Specifically, there are 2 electrons in the first shell and 7 electrons in the second shell.