Question

Match the atomic numbers 4, 14, 8, 15 and 19 with solid non-metal of valency 3.
A)$8$
B)$14$
C)$15$
D)$19$

Answer 1

Hint: We know that the electrons within the outermost shell are called valence electrons and therefore the number of electrons it accepts or donates to make a bond is named the valency of an electron. If the outermost shell isn't filled then to fill the outermost shell, it accepts or donates electrons between other atoms.

Complete answer:
We have to remember that the representative components are the compound components in the gathering $1$, bunch $2$ and in the groups from $13$ to $18$. Delegate components are otherwise called bunch A components or s-block components and p-block components or fundamental gathering components.
As we know that the S-block components have their valence electrons in the furthest s-orbitals and are in two sorts as soluble base metals and basic earth metals. Salt metals are bunch $1$ while antacid earth’s metals are bunch $2$ components p-block components have their valence electrons in the peripheral p-orbitals. Practically all the p-block components are non-metals including some metalloid.
We know that the atomic number 8 belongs to the oxygen with electronic configuration of beryllium is $1{s^2}2{s^2}2{p^4}$ in which the valency of oxygen is 2. Therefore, the option A is incorrect.
As we know that the atomic number of 14 belongs to the silicon with electronic configuration of $1{s^2}2{s^2}2{p^6}3{s^2}3{p^2}$ and silicon is a metalloid. Therefore, the option B is incorrect.
As we know that the atomic number 19 belongs to the potassium which having the electronic configuration of $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^1}$ and potassium is the alkali metal. Therefore, the option D is incorrect.
Atomic number $15$ is phosphorus with electronic configuration of $1{s^2}2{s^2}2{p^6}3{s^3}3{p^2}$ so it need three more electron to finish octet and have valency of three. P is strong non-metal.
Therefore, the correct option is C.

Note:
Now we discuss how metals, nonmetals and metalloids differ from each other.
-Metals:
We have to remember that the metals are the components which are gleaming materials and great conduits of warmth and power. All metals are solids at room temperature aside from mercury, which is a fluid.
-Non-metals:
We have to know that the nonmetals are the components which don't have a sparkly appearance and non-metals are commonly helpless transmitters of warmth and power.
-Metalloids:
Metalloids are the components which have properties halfway among metals and non-metals. Just seven components are ordered as metalloids.