In Figure 8, the letters A, E, G, J, X and Z show the positions of six elements in the periodic table - Edexcel - GCSE Chemistry - Question 8 - 2019 - Paper 1
Question 8
In Figure 8, the letters A, E, G, J, X and Z show the positions of six elements in the periodic table. These letters are not the symbols of the atoms of these elemen... show full transcript
Worked Solution & Example Answer:In Figure 8, the letters A, E, G, J, X and Z show the positions of six elements in the periodic table - Edexcel - GCSE Chemistry - Question 8 - 2019 - Paper 1
Step 1
Using the letters A, E, G, J and Z (i) give the letters of the two elements that are non-metals.
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Answer
The two elements that are non-metals are A and J.
Step 2
Using the letters A, E, G, J and Z (ii) give the letters of two elements in period 2.
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Answer
The two elements in period 2 are E and J.
Step 3
Using the letters A, E, G, J and Z (iii) give the letter of an element that normally forms an ion with a charge of +1.
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Answer
The element that normally forms an ion with a charge of +1 is J.
Step 4
All atoms of element E in this sample contain
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Answer
Element E must contain 5 protons, so the correct answer is A.
Step 5
Element X has an atomic number of 18. State the electronic configuration of an atom of element X.
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Answer
The electronic configuration of element X is 2.8.8.
Step 6
In an experiment, 3.5 g of element A reacted with 4.0 g of element G to form a compound. Calculate the empirical formula of this compound.
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Answer
To find the empirical formula:
Calculate the moles of each element:
Moles of A = \frac{3.5 ext{ g}}{7 ext{ g/mol}} = 0.5 ext{ mol}
Moles of G = \frac{4.0 ext{ g}}{16 ext{ g/mol}} = 0.25 ext{ mol}
Divide by the smallest number of moles:
Ratio of A to G = \frac{0.5}{0.25} : \frac{0.25}{0.25} = 2:1.
Thus, the empirical formula is A₂G.
Step 7
An oxygen atom has six electrons in its outer shell. A hydrogen atom has one electron in its outer shell. Complete the dot and cross diagram of a molecule of water, H₂O.
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Answer
In the dot and cross diagram for water (H₂O):
The oxygen atom (O) is represented at the center with six outer shell electrons, shown as dots.
The two hydrogen atoms (H) will be shown as crosses with one outer shell electron each. The diagram shows how the oxygen atom shares its electrons with both hydrogen atoms.
