8 (a) An atom of potassium has atomic number 19 and mass number 39 - Edexcel - GCSE Chemistry - Question 8 - 2020 - Paper 1
Question 8
8 (a) An atom of potassium has atomic number 19 and mass number 39.
(i) Give the electronic configuration of this potassium atom.
(ii) This potassium atom forms th... show full transcript
Worked Solution & Example Answer:8 (a) An atom of potassium has atomic number 19 and mass number 39 - Edexcel - GCSE Chemistry - Question 8 - 2020 - Paper 1
Step 1
Give the electronic configuration of this potassium atom.
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Answer
The electronic configuration of potassium (K) with atomic number 19 is 2.8.8.1.
Step 2
Which row shows the number of protons and the number of neutrons in this potassium ion, K⁺?
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Answer
The potassium ion K⁺ has 19 protons and 20 neutrons, meaning the correct row is B.
Step 3
Explain, in terms of electrons, why potassium and caesium are in the same group.
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Answer
Both potassium and caesium are in Group 1 of the periodic table, which is characterized by having one electron in their outer shell. This similar electron configuration results in similar chemical properties, such as reactivity.
Step 4
Explain, in terms of these forces, why the boiling point of fluorine is low.
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Answer
Fluorine has weak Van der Waals forces between its molecules. These weak intermolecular forces require little energy to overcome, hence resulting in a low boiling point of -188 °C.
Step 5
Complete the balanced equation for this reaction and add the state symbols.
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Answer
The balanced equation is:
K (s) + F₂ (g) → KF (s)
Step 6
What are the elements in group 1 of the periodic table called?
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Answer
The elements in group 1 of the periodic table are called alkali metals.
Step 7
Give, using Figure 14, the boiling point of bromine.
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Answer
The boiling point of bromine, according to Figure 14, is approximately 59 °C.
Step 8
State which two elements from Figure 14 are solids at room temperature.
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Answer
The two elements from Figure 14 that are solids at room temperature are iodine and astatine.
