Question

1. helium, like other noble gases, has a full, and therefore stable, outermost electron shell structure. how many electrons are in heliums outermost shell? what about the other noble gas elements? why is there a difference? helium has 2 electrons and noble gas has 8 electrons. 2. how can metal elements achieve a stable electron - shell structure like those of the noble gases? 3. how can non - metal elements achieve a stable electron - shell structure like that of the noble gases?

Explanation:

1. Helium has 2 electrons in its outermost shell as it has only one electron - shell (K - shell which can hold a maximum of 2 electrons). Other noble - gas elements (Ne, Ar, Kr, Xe, Rn) have 8 electrons in their outermost shell because their outermost shells are higher - energy shells (L, M, N etc.) which can hold a maximum of 8 electrons to be stable according to the octet rule.
2. Metal elements achieve a stable electron - shell structure like noble gases by losing electrons. They have few electrons in their outermost shell (usually 1 - 3), and by losing these electrons, they can attain a stable electron configuration of the previous noble - gas element.
3. Non - metal elements achieve a stable electron - shell structure like noble gases by gaining electrons or sharing electrons. Non - metals usually have 4 - 7 electrons in their outermost shell. By gaining electrons, they can complete their outermost shell to have 8 electrons (except hydrogen which aims for 2 electrons). They can also share electrons with other non - metals to form covalent bonds and achieve a stable electron configuration.

Answer:

1. Helium has 2 electrons in its outermost shell. Other noble - gas elements (except helium) have 8 electrons in their outermost shell. The difference is due to the fact that helium has only a K - shell which can hold a maximum of 2 electrons, while other noble gases have higher - energy shells (L, M, N etc.) that can hold 8 electrons to be stable.
2. Metal elements achieve a stable electron - shell structure like noble gases by losing electrons.
3. Non - metal elements achieve a stable electron - shell structure like noble gases by gaining or sharing electrons.