Why do He and Ne then have different numbers of electrons in their outer shells?
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Help Please..
The family or column number will tell you the number of outer electrons for each element in that family. There are some exceptions....the transition metals and Helium.
Number of Electrons in the
Outer Shell with element name:
1 Hydrogen
2 Helium (shell complete)
1 Lithium
2 Beryllium
3 Boron
4 Carbon
5 Nitrogen
6 Oxygen
7 Fluorine
8 Neon (shell complete)
He and Ne refer to the elements helium and neon, which are located in the second period of the periodic table.
To understand why they have different numbers of electrons in their outer shells, we need to consider the electron configuration of each element.
Helium (He) has an atomic number of 2, meaning it contains 2 electrons. Its electron configuration is 1s², indicating that its only energy level (shell) is the first shell, and it has a total of 2 electrons occupying the 1s orbital.
Neon (Ne), on the other hand, has an atomic number of 10 and contains 10 electrons. Its electron configuration is 1s² 2s² 2p⁶. This configuration shows that neon has two electrons in the first shell (1s²), followed by 8 electrons in the second shell (2s² 2p⁶).
The reason Helium (He) and Neon (Ne) have different numbers of electrons in their outer shells is because of the way the periodic table is organized. Elements in the same group (vertical column) have similar chemical properties and tend to have the same number of valence electrons (electrons in the outermost shell).
In the case of helium, it is located in group 18, known as the noble gases. Noble gases have full outer shells and are highly stable. In the case of helium, its 1s orbital is completely filled with 2 electrons, making it a stable configuration.
Neon, located in the same group as helium, also belongs to the noble gases. It has a stable electron configuration with a full outer shell. In the case of neon, its second shell (2s² 2p⁶) is completely filled with 8 electrons, resulting in a stable configuration.
Therefore, while helium (He) and neon (Ne) have different numbers of electrons in their outer shells, they both have stable configurations, which is why they are considered chemically inert and have low reactivity.