5. The reactivity of an element is determined by the number and arrangement of electrons around the nucleus in each of its atoms - Leaving Cert Chemistry - Question 5 - 2020
Question 5
5. The reactivity of an element is determined by the number and arrangement of electrons around the nucleus in each of its atoms. Around 1913 Bohr proposed that elec... show full transcript
Worked Solution & Example Answer:5. The reactivity of an element is determined by the number and arrangement of electrons around the nucleus in each of its atoms - Leaving Cert Chemistry - Question 5 - 2020
Step 1
What is an electron?
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Answer
An electron is a subatomic particle that orbits the nucleus of an atom. It is negatively charged and has a very small mass, approximately 1/1840 of a hydrogen atom.
Step 2
Why might the electron in a hydrogen atom not occupy the n = 1 energy level?
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Answer
The electron may not occupy the n = 1 energy level if it has absorbed energy and moved to a higher energy level.
Step 3
What colour light is associated with the electron in a hydrogen atom moving from n = 3 to n = 2?
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The colour of light associated with this transition is red.
Step 4
Name the series of visible lines in the hydrogen emission spectrum.
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The series of visible lines is known as the Balmer series.
Step 5
How many sub-levels are associated with the n = 3 energy level?
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There are three sub-levels associated with the n = 3 energy level.
Step 6
What is an atomic orbital?
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An atomic orbital is a region in space around the nucleus where there is a high probability of finding an electron.
Step 7
How many orbitals are associated with the n = 2 energy level?
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There are four orbitals associated with the n = 2 energy level.
Step 8
What is the maximum number of electrons that can occupy the n = 3 energy level in a multi-electron atom?
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The maximum number of electrons that can occupy the n = 3 energy level is 18.
Step 9
Write electron configurations for beryllium, neon, magnesium and krypton.
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Why are the Group 18 elements neon and krypton chemically inert?
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Answer
Group 18 elements have full outer shells (8 electrons) which makes them stable and unreactive.
Step 11
Why are the Group 2 elements beryllium and magnesium reactive?
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Beryllium and magnesium do not have full outer shells, making them unstable and more likely to react to achieve stability.
Step 12
Why is magnesium more reactive than beryllium?
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Magnesium has a larger atomic radius and more energy levels than beryllium, which means the outer electrons are held less tightly and can be lost more easily.
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