3.5.1 - Electron Shells
As discussed previously, the shells in an atom or ion are the paths that the electrons take as they orbit the nucleus.
The electron shells are numbered starting from the innermost shell, which is called the first shell. The next shell out is called the second shell, and so on.
Electron shells are also known as energy levels. This is because electrons in different shells have different amounts of energy. The electrons in the first shell (the one closest to the nucleus) have the lowest amount of energy. As you move out through the shells, the energy of the electrons increases.
The shells are numbered from the centre outwards. The electrons in the first shell (the one closest to the nucleus) have the lowest amount of energy. As you move out through the shells, the energy of the electrons increases.
The energy of the electrons allows they to partly overcome the electrostatic attraction that is pulling them towards the nucleus.
If the electrons had no energy, they would be pulled into the nucleus, due to their attraction to the positively charged protons.
Their energy allows them to orbit at a distance from the nucleus, rather than being pulled in. The more energy an electron has, the more it is able to overcome the attraction and therefore the further away from the nucleus it will orbit. This is why the energy of the electrons increases as you go out through the shells.
Flashcards help you memorise information quickly. Copy each question onto its own flashcard and then write the answer on the other side. Testing yourself on these regularly will enable you to learn much more quickly than just reading and making notes.
How are the electron shells numbered?
What are electron shells also known as? Why?
How does the energy of the electrons vary between the shells?
How does the energy of an electron affect the distance from the nucleus at which it orbits?
3.5.2 - The Capacities of the Shells
3.4.3 - Metals, Nonmetals and Metalloids
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