Question

Name the type of elements, which have their
1. outermost shell complete
2. outermost shell incomplete
3. two outermost shell incomplete
4. one electron short of octet
5. two electrons in the outermost orbit.

Answer 1

The number of electrons in an atom's outermost shell has an effect on its reactivity, or its ability to form chemical bonds with other atoms. The valence shell is the outermost shell, and valence electrons are the electrons that reside there.

Complete answer:
1. The elements which have their outermost shell complete are called noble gases. This group has eight electrons in its outermost orbit (except helium which has two electrons). As a result, they have a stable arrangement. Group $18$ elements are gases with a low chemical reactivity, meaning they don't form many compounds.
2. The elements which have their outermost shell incomplete are called representative elements. Representative Elements are the elements in the modern periodic table that include the $s$ and $p$ block.
3. The elements which have their two outermost shells incomplete are called transition elements. Transition elements are elements with partially filled $d -$ orbital.
4. The elements which have one electron short of octet are called halogens. Halogens are known as non-metals. The reactivity of halogens decreases as they progress from fluorine to astatine. In nature, halogens do not exist in their elemental form.
5. The elements which have two electrons in the outermost orbit are called alkaline earth metals. Alkaline earth metals are the elements that make up the group $2$ of the modern periodic table.

Note:
The outermost shells of elements in the same group have the same number of electrons, resulting in identical valence shell electronic configurations. As a result, the characteristics and chemistry of elements in the same group follow a similar pattern.