In Figure 5, the letters A, E, G, J, X and Z show the positions of six elements in the periodic table - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2019 - Paper 1
Question 5
In Figure 5, 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 5, the letters A, E, G, J, X and Z show the positions of six elements in the periodic table - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2019 - Paper 1
Step 1
Using the letters A, E, G, J, X and Z
(i) give the letters of the two elements that are non-metals.
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Answer
The two non-metals are E and J.
Step 2
Using the letters A, E, G, J, X 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 G.
Step 3
Using the letters A, E, G, J, X 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 A.
Step 4
All atoms of element E in this sample contain
(iv)
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Answer
The correct answer is A: 5 protons.
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 calculate the empirical formula, we first find the number of moles of each element:
For element A:
ext{Moles of A} = rac{3.5 ext{ g}}{7 ext{ g/mol}} = 0.5 ext{ mol}
For element G:
ext{Moles of G} = rac{4.0 ext{ g}}{16 ext{ g/mol}} = 0.25 ext{ mol}
Next, divide both by the smallest number of moles:
ext{Ratio of A:G} = rac{0.5}{0.25} : rac{0.25}{0.25} = 2:1
Thus, the empirical formula of the compound 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.
Show outer shell electrons only.
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Answer
The dot and cross diagram for the water molecule is shown below with:
Oxygen represented as a cross (X) and hydrogen as dots (•):
H• O×××
/ \
•H •
In this diagram, the shared electrons between the atoms represent the bonds formed.
